Rome's Lost Empire

0:00:02 > 0:00:04'The Roman Empire.

0:00:04 > 0:00:06'With its Coliseum,

0:00:06 > 0:00:09'its gladiators

0:00:09 > 0:00:10'and its ancient cities...

0:00:12 > 0:00:14'..frozen in time.

0:00:17 > 0:00:21'No other power dominated the planet for so long.

0:00:21 > 0:00:24'But what are the secrets that helped Rome rule?

0:00:27 > 0:00:30'It remains one of history's greatest riddles.

0:00:32 > 0:00:34'Until now.'

0:00:34 > 0:00:37There are about 60 features that have appeared

0:00:37 > 0:00:41which show up in these red circles.

0:00:42 > 0:00:44'By using satellites,

0:00:44 > 0:00:48'one archaeologist will uncover a Rome

0:00:48 > 0:00:51'that no-one knew existed.

0:00:51 > 0:00:55'Finding buried settlements,

0:00:55 > 0:00:57'forgotten forts,

0:00:57 > 0:01:01'and lost amphitheatres.'

0:01:01 > 0:01:02It's never been discovered before?

0:01:02 > 0:01:06As far as I know, it is a completely new structure.

0:01:06 > 0:01:08'I'm Dan Snow,

0:01:08 > 0:01:11'a broadcaster with a passion for history.'

0:01:11 > 0:01:1550,000 people would have packed into here.

0:01:15 > 0:01:20'This is my chance to join this revolution in archaeology.'

0:01:20 > 0:01:24Wow, that's wonderful! That looks like a Roman fort.

0:01:24 > 0:01:28'Together, we'll journey to the four corners of the Roman Empire.'

0:01:28 > 0:01:31There's a fork in the road here, do you want me to right or left?

0:01:31 > 0:01:35I think we just continue on ahead, according to my GPS.

0:01:35 > 0:01:38'From the mountains and rivers of Europe...'

0:01:38 > 0:01:40Can you see? I'm touching it now.

0:01:42 > 0:01:45'..to the hot deserts of the Middle East.'

0:01:45 > 0:01:46It's a very special place for me

0:01:46 > 0:01:48because I came here with my mum and dad when I was a kid.

0:01:48 > 0:01:51'Across the vast interior of Africa...'

0:01:51 > 0:01:54What the satellites are showing us is just...

0:01:54 > 0:01:56There's so much more left to find.

0:01:56 > 0:01:59'..to the glory of Rome itself.'

0:01:59 > 0:02:01That is awesome!

0:02:03 > 0:02:08'And, guided by best Roman archaeologists in the world...'

0:02:08 > 0:02:10How amazing is this view?

0:02:10 > 0:02:11'..tell the real story...

0:02:14 > 0:02:16'..of how Rome ruled.'

0:02:33 > 0:02:37'Our journey begins not in the old world but the new.

0:02:37 > 0:02:40'In America's Deep South.'

0:02:52 > 0:02:56I've always been absolutely fascinated by the Roman Empire.

0:02:56 > 0:02:59I think it was cos as a kid my mum and dad dragged me

0:02:59 > 0:03:01round the Roman sites, like Hadrian's Wall,

0:03:01 > 0:03:03and that really fired my imagination.

0:03:06 > 0:03:08And then as I've grown older,

0:03:08 > 0:03:11I've studied the Roman Army tactics and technology,

0:03:11 > 0:03:13fighting those battles the legend of which

0:03:13 > 0:03:16echoed down across the centuries.

0:03:16 > 0:03:19But there's always been one thing about Rome

0:03:19 > 0:03:21that's absolutely intrigued me.

0:03:25 > 0:03:28'At its height, the Roman Empire was vast.

0:03:29 > 0:03:31'Pushing out from Rome,

0:03:31 > 0:03:34'through modern-day Germany, France and Spain,

0:03:34 > 0:03:37'up into drizzle-soaked Northern England.

0:03:39 > 0:03:43'Stretching eastwards over the mountains of Middle Europe...

0:03:44 > 0:03:49'..all the way to the sun-baked deserts of Syria and Jordan.

0:03:50 > 0:03:55'And south, across the immense, rich plains of the North African coast.

0:03:58 > 0:04:03'This was an Empire that covered five million square miles

0:04:03 > 0:04:06'and had a population of at least 60 million people.

0:04:08 > 0:04:14'That left Rome's army, of around 300,000 troops,

0:04:14 > 0:04:16'massively outnumbered.

0:04:16 > 0:04:18'200 to one.'

0:04:21 > 0:04:24Yes, the Roman Army was the best in the world.

0:04:24 > 0:04:29But, at the same time, how could Rome rule over such a vast empire

0:04:29 > 0:04:32with such a small number of professional troops?

0:04:32 > 0:04:34It's a question that's always baffled me.

0:04:34 > 0:04:37That's why I've come to Birmingham, Alabama, in the United States

0:04:37 > 0:04:40to meet a woman who I think is going to help me find an answer.

0:04:43 > 0:04:47'Dr Sarah Parcak is an associate professor of archaeology

0:04:47 > 0:04:50'at Alabama State University.'

0:04:50 > 0:04:52There have been a number of cases throughout history

0:04:52 > 0:04:55where people have used identity...

0:04:55 > 0:04:59'By day, she's a regular college lecturer.'

0:04:59 > 0:05:02..truly crusader period. I mean, it had a big arrow through its chest.

0:05:02 > 0:05:05'But at night, it's a different story.'

0:05:05 > 0:05:07When I was a small girl,

0:05:07 > 0:05:10I always used to imagine myself on a rocket ship.

0:05:12 > 0:05:14I'm going to be finding other planets,

0:05:14 > 0:05:16we're going to be meeting aliens.

0:05:18 > 0:05:21Here we are, we're in this lab.

0:05:21 > 0:05:25You know, it's like... it's like I'm in that spaceship.

0:05:26 > 0:05:31'Sarah is a pioneer in the new science of space archaeology.'

0:05:32 > 0:05:36The vehicle for exploration is a computer.

0:05:36 > 0:05:39There are thousands...hundreds of thousands of archaeological sites

0:05:39 > 0:05:43and features all over the world that haven't been found yet.

0:05:43 > 0:05:44And I know they're out there to be found.

0:05:46 > 0:05:49And if you hit the right button, it will just pop out in front of you.

0:05:49 > 0:05:53That moment of discovery, that a-ha moment,

0:05:53 > 0:05:55that's like you're landing the ship on another planet.

0:05:55 > 0:05:57And the doors are opening for the first time

0:05:57 > 0:05:59onto a completely new world.

0:06:07 > 0:06:12'She's using satellites orbiting 500 miles above the earth.

0:06:14 > 0:06:17'They are equipped with high-resolution cameras

0:06:17 > 0:06:20'developed by the military for spying.

0:06:21 > 0:06:24'These satellites can pinpoint objects

0:06:24 > 0:06:27'less than a metre in diameter on the earth's surface.

0:06:33 > 0:06:38'12 months ago, Sarah had huge success in Egypt...'

0:06:38 > 0:06:43For the whole of upper Egypt, I have found over 1,200 ancient sites.

0:06:43 > 0:06:50'..uncovering long-lost temples, tombs and even pyramids...

0:06:52 > 0:06:55'..using satellites to change our understanding

0:06:55 > 0:06:59'of Egyptian civilisation for ever.'

0:07:00 > 0:07:04All right, Dan. So I want to show you how this technology works.

0:07:04 > 0:07:09So we're going to go to an Egyptian settlement.

0:07:09 > 0:07:12And what you're really seeing is the equivalent of

0:07:12 > 0:07:15an aerial photograph but taken from space.

0:07:15 > 0:07:18And what we do is, we combine the higher resolution technology

0:07:18 > 0:07:22with infrared technology to get this.

0:07:23 > 0:07:25- Wow.- So really what you're seeing

0:07:25 > 0:07:29are the outlines of buildings, structures and even ancient streets.

0:07:29 > 0:07:32That's like a map of downtown Manhattan.

0:07:32 > 0:07:37But, you know, I have to say, this is really the technology at its best.

0:07:37 > 0:07:41'This time, the task will be much harder.

0:07:41 > 0:07:45'The Roman Empire was six times bigger than Egypt

0:07:45 > 0:07:47'and not simply desert,

0:07:47 > 0:07:52'but a multitude of complex landscapes and terrains.'

0:07:52 > 0:07:55There's an area here in Romania,

0:07:55 > 0:07:58and we're very, very interested in this area.

0:07:58 > 0:08:00We know that something interesting might be here.

0:08:00 > 0:08:02But, unfortunately, there's a problem.

0:08:04 > 0:08:05There are a lot of trees.

0:08:05 > 0:08:10There are many trees, and satellites simply cannot see through trees,

0:08:10 > 0:08:11it's impossible.

0:08:11 > 0:08:13OK, that is a challenge.

0:08:13 > 0:08:15This is something we are working through right now.

0:08:15 > 0:08:17OK, this is the thing, the bottom line is,

0:08:17 > 0:08:20are you going to come with me around the Roman Empire?

0:08:20 > 0:08:23And can you and your technology help solve this central riddle

0:08:23 > 0:08:26of how this empire was ruled?

0:08:26 > 0:08:29Because if you deliver, if this technology delivers,

0:08:29 > 0:08:32these could be some of the biggest breakthroughs in Roman history

0:08:32 > 0:08:34for hundreds of years.

0:08:34 > 0:08:37Yeah, I am definitely up for this challenge,

0:08:37 > 0:08:40but this technology, it's not without its limitations.

0:08:40 > 0:08:43So, on the one hand, I'm really, really excited

0:08:43 > 0:08:46about what we might possibly find, but on the other hand,

0:08:46 > 0:08:49I'm also pretty, pretty nervous.

0:09:03 > 0:09:07I guess there is that jeopardy of finding out whether or not

0:09:07 > 0:09:10I really am an expert at doing this.

0:09:20 > 0:09:25Running is where I can really clear my head

0:09:25 > 0:09:27and allow myself time to think.

0:09:38 > 0:09:39I am determined.

0:09:39 > 0:09:44I'm a pretty focused person once I set my mind to something.

0:09:44 > 0:09:47I'll just run into a brick wall until it falls over.

0:09:50 > 0:09:51That's not always wise,

0:09:51 > 0:09:54because you end up getting quite bruised and bloodied.

0:09:55 > 0:09:58But eventually there are cracks that show up.

0:10:06 > 0:10:09'Our quest begins in the capital city of Italy.

0:10:09 > 0:10:13'Rome, where else?

0:10:18 > 0:10:23'At the height of the Roman Empire, roughly the first two centuries AD,

0:10:23 > 0:10:27'this was the most extraordinary city on the planet.

0:10:30 > 0:10:37'Crammed with glittering palaces, triumphal arches and amphitheatres.'

0:10:37 > 0:10:40- There you go.- That is awesome. - The Coliseum.

0:10:40 > 0:10:45'It seems the obvious place to begin. Or is it?

0:10:55 > 0:10:58'We are heading 20 miles west, along the River Tiber...

0:11:02 > 0:11:04'..to a place now long forgotten.

0:11:09 > 0:11:12'It's said to be the lost jewel.

0:11:12 > 0:11:15'The glittering secret behind Rome's success.

0:11:18 > 0:11:21'Which could provide vital clues...

0:11:21 > 0:11:23That is awesome.

0:11:23 > 0:11:26'..as to how it ruled its vast Empire.

0:11:32 > 0:11:34'This is Portus...

0:11:35 > 0:11:38'..the once-great harbour of Rome.

0:11:40 > 0:11:44'For 500 years, the most important seaport in the entire world.

0:11:48 > 0:11:52'At its heart was a gigantic hexagonal basin,

0:11:52 > 0:11:53'still here today...

0:11:55 > 0:11:58'..big enough to berth 150 ships.

0:12:00 > 0:12:05'Which, 2,000 years ago, was attached to an even great basin,

0:12:05 > 0:12:07'six times as large.

0:12:11 > 0:12:13'A series of canals have been identified

0:12:13 > 0:12:15'which once linked the harbour to Rome.

0:12:20 > 0:12:23'But there are huge gaps in our knowledge.

0:12:23 > 0:12:28'And to know how this port complex actually worked might give us

0:12:28 > 0:12:33'a better understanding of what made the Empire as a whole tick.

0:12:35 > 0:12:38'But it's a mind-boggling challenge.

0:12:40 > 0:12:46'Over thousands of years, the sea has receded three miles to the west

0:12:46 > 0:12:50'and much of the harbour is now buried

0:12:50 > 0:12:55'beneath a chaos of suburbs, flyovers and roads

0:12:55 > 0:12:57'on the edge of Fiumicino Airport.

0:13:07 > 0:13:09'While Sarah sets up her base of operations,

0:13:12 > 0:13:15'I'm off to meet the world expert on Portus,

0:13:15 > 0:13:20'the renowned British archaeologist Professor Simon Keay.

0:13:22 > 0:13:24'He's here leading a team

0:13:24 > 0:13:27'which, once the weather breaks,

0:13:30 > 0:13:32'hopes to excavate the site.

0:13:33 > 0:13:37'In the meantime I'm grabbing a moment to learn more about the harbour.'

0:13:39 > 0:13:42Why did Rome need this great big port right next door to it?

0:13:42 > 0:13:44Well, that's actually a very good question.

0:13:44 > 0:13:45I think you have to remember that

0:13:45 > 0:13:49Rome was an exceptional pre-industrial city,

0:13:49 > 0:13:50nearly a million people.

0:13:50 > 0:13:54And a million people living in an imperial capital.

0:13:54 > 0:13:57So you need food on an unparalleled scale,

0:13:57 > 0:13:59in a pre-industrial society.

0:13:59 > 0:14:02You also need all the effects,

0:14:02 > 0:14:05materials that dignify an imperial capital.

0:14:05 > 0:14:09Like marble, silks, gold statues and everything else.

0:14:10 > 0:14:15'Simon has spent his career building up a picture of how Portus worked.

0:14:18 > 0:14:22'But, after years of digging, it's still not making sense.

0:14:23 > 0:14:29'He's hoping that Sarah's technology can help complete the puzzle.'

0:14:29 > 0:14:31What would you like Sarah to look for?

0:14:31 > 0:14:33What would it be great if she found?

0:14:33 > 0:14:37What she really needs to focus on is canals, primarily,

0:14:37 > 0:14:42because what we don't know so much about is how all this worked.

0:14:42 > 0:14:47But I guess the real special thing to find, it would be too much to ask,

0:14:47 > 0:14:52but one just hopes that maybe by looking at satellite imagery

0:14:52 > 0:14:57we can add...we can add more to or perhaps even find

0:14:57 > 0:15:00the great lighthouse of Portus.

0:15:05 > 0:15:07'The lighthouse of Portus

0:15:07 > 0:15:10'is one of the lost Wonders of the Ancient World

0:15:10 > 0:15:14'and was said to be visible from over 20 miles out to sea.

0:15:18 > 0:15:21'Sought after by archaeologists for centuries,

0:15:21 > 0:15:25'it's considered the ultimate symbol of Roman power.

0:15:26 > 0:15:30'And finding hard physical evidence for its existence

0:15:30 > 0:15:34'would be one of the greatest finds of Simon's career.'

0:15:45 > 0:15:47- Sarah, how's it going? You've been here all night.- Hey, Dan.

0:15:47 > 0:15:50- Burning the midnight oil. - Looking good?

0:15:50 > 0:15:54Well, not, er...not quite.

0:15:54 > 0:15:58I mean, this is, this is a really, really difficult landscape.

0:15:58 > 0:16:02You've got tons of urbanisation, which you can see here.

0:16:02 > 0:16:05You know, I've been looking up here

0:16:05 > 0:16:10and, you know, things that I think might possibly be ancient

0:16:10 > 0:16:13turn out to be modern the more I look at them, so

0:16:13 > 0:16:16it's pretty complicated and I'm still trying to get my head around it.

0:16:16 > 0:16:19I don't really understand this, there's not much I can do to help,

0:16:19 > 0:16:22- so I'm going to get some sleep, you keep at it.- Lucky you, Dan.

0:16:56 > 0:17:00'After working all night, Sarah has found...

0:17:00 > 0:17:01'nothing.

0:17:01 > 0:17:06'And the reality of what she's set out to do finally hits home.'

0:17:06 > 0:17:11We're in the middle of this blighted urban wasteland.

0:17:11 > 0:17:14I keep thinking, how is it that the satellite imagery

0:17:14 > 0:17:17can possibly show us what might be here?

0:17:21 > 0:17:24There's really nothing here that's visible

0:17:24 > 0:17:29that hints of the glory of this once-great port of Rome.

0:17:34 > 0:17:37Maybe I'm naive in thinking that it will work this time.

0:17:38 > 0:17:42Maybe I have bitten off more than I can chew.

0:17:47 > 0:17:49'We are not giving up on Portus.

0:17:49 > 0:17:52'But with Sarah clearly struggling with her satellites,

0:17:52 > 0:17:55'it's time for me to take temporary charge.

0:17:57 > 0:18:01'To understand how Rome ruled its vast Empire,

0:18:01 > 0:18:03'there are several key areas to look at.

0:18:06 > 0:18:08'But for me, as a military historian,

0:18:08 > 0:18:11'there is only one place now to go.

0:18:16 > 0:18:19'Transylvania.

0:18:19 > 0:18:22'Dark. Impenetrable.

0:18:23 > 0:18:26'And in the Second Century AD,

0:18:26 > 0:18:31'a mountain kingdom ruled by a tribe the Romans dismissed as barbarians.

0:18:35 > 0:18:39'We're leaving Portus for now and heading to Transylvania,

0:18:39 > 0:18:41'part of modern-day Romania.

0:18:43 > 0:18:47'Because what happened here is the best example I know

0:18:47 > 0:18:50'of the Roman Army at its most ruthless.

0:18:54 > 0:18:59'From deep in the forest, a barbarian tribe called the Dacians

0:18:59 > 0:19:02'were getting too big for their boots -

0:19:02 > 0:19:04'raiding Roman territory,

0:19:04 > 0:19:07'stealing livestock and women,

0:19:07 > 0:19:10'and giving the greatest empire on earth

0:19:10 > 0:19:12'the proverbial two-finger salute.

0:19:14 > 0:19:19'By themselves the Dacian barbarians posed no real threat.

0:19:19 > 0:19:23'But Rome had built its reputation on ruthlessness.

0:19:26 > 0:19:29'Rome understood that, if it showed any sign of weakness,

0:19:29 > 0:19:33'similar rebellions could rise up right across the Empire.

0:19:35 > 0:19:38'The Dacians had to be made an example of.

0:19:42 > 0:19:44'Including their renegade leader.

0:19:47 > 0:19:50'Now a martyr, and symbol of rebellion.

0:19:52 > 0:19:54'This is Decebalus.

0:19:54 > 0:19:57'King of the Dacians.

0:20:04 > 0:20:08'Rome had military commitments right across its vast empire,

0:20:08 > 0:20:11'but it knew it had to prove a point.

0:20:11 > 0:20:15'It threw an astonishing 60,000 men at the Dacians,

0:20:15 > 0:20:19'and in doing so sent out a clear message.

0:20:20 > 0:20:23'Never mess with Rome.

0:20:29 > 0:20:31'But to get at the Dacians,

0:20:31 > 0:20:33'the Romans first had to cross

0:20:33 > 0:20:39'one of the most formidable natural barriers in the entire world.

0:20:42 > 0:20:48'Nearly a mile wide, fast flowing, with murderous currents -

0:20:48 > 0:20:50'the mighty Danube river.

0:20:59 > 0:21:02'What's most remarkable is how they did it.'

0:21:11 > 0:21:13It's going to be a very challenging dive today.

0:21:13 > 0:21:15The Danube is difficult at the best of times.

0:21:15 > 0:21:19You can see the way this current swirls around, racing down there towards the Black Sea,

0:21:19 > 0:21:22and the visibility looks particularly bad.

0:21:22 > 0:21:23So lots of things to worry about.

0:21:23 > 0:21:26So we've managed to notify International Shipping

0:21:26 > 0:21:28and it's time to go for it.

0:21:31 > 0:21:32OK, Johnny?

0:21:34 > 0:21:36Are we ready to go on this, gentlemen?

0:21:51 > 0:21:53It's quite hard going, there's a lot of current.

0:21:53 > 0:21:55Very, very slow.

0:22:00 > 0:22:05You might want to try going down to the base of the river,

0:22:05 > 0:22:09just so you can crawl along, over, so I can give you directions.

0:22:18 > 0:22:21OK, I'm getting close to what looks like the bottom here.

0:22:22 > 0:22:24Wow, there's a lot of current down here.

0:22:25 > 0:22:27Making very slow progress.

0:22:30 > 0:22:33The water's whipping around you pretty quickly,

0:22:33 > 0:22:34be careful down there, Dan.

0:22:38 > 0:22:42Just dragging myself along the floor of this riverbed.

0:22:42 > 0:22:44There's a lot of current.

0:22:48 > 0:22:53It looks like it should be here somewhere, close by.

0:22:53 > 0:22:57Why don't you try going about three or four metres to your right?

0:22:57 > 0:23:00I think you're a bit off at the moment.

0:23:09 > 0:23:11Sarah, I can see...

0:23:12 > 0:23:13I can see something.

0:23:13 > 0:23:17It's very hard to tell through this incredibly bad visibility.

0:23:18 > 0:23:22I'm beginning to make out the faint outline of something.

0:23:22 > 0:23:24Describe to me what you're seeing, Dan.

0:23:34 > 0:23:37Can you see? I'm touching it now.

0:23:38 > 0:23:44It's clearly what appears to be the footings of a bridge.

0:23:46 > 0:23:51Some brickwork. You can see the mortar. It's pretty overgrown now.

0:23:52 > 0:23:55But I think what we're seeing here is the evidence of

0:23:55 > 0:23:57the Roman bridge across the Danube.

0:24:00 > 0:24:03'And not just any old bridge.

0:24:03 > 0:24:07'It was the longest bridge in the entire world...

0:24:09 > 0:24:12'..nearly a mile from bank to bank.

0:24:14 > 0:24:17'One of the biggest works of military architecture

0:24:17 > 0:24:20'in the history of the Roman Empire.'

0:24:26 > 0:24:29Well, that was... that was just incredible.

0:24:29 > 0:24:31Definitely saw the footings of the Roman bridge.

0:24:31 > 0:24:34It's an incredible testament to the engineering prowess

0:24:34 > 0:24:37of the Roman Army that, even after 2,000 years

0:24:37 > 0:24:40on one of the fastest and busiest rivers on the planet,

0:24:40 > 0:24:42it's still there.

0:24:50 > 0:24:53This really was a titanic undertaking,

0:24:53 > 0:24:57and it took them around about two years. A long time.

0:24:57 > 0:24:59But actually, I think the Romans would have potentially

0:24:59 > 0:25:01seen that as an advantage.

0:25:01 > 0:25:05There's something crushingly inevitable about the slow progress

0:25:05 > 0:25:07of this bridge across this mighty river.

0:25:07 > 0:25:10You can just imagine the Dacians standing on the other side,

0:25:10 > 0:25:13seeing it edge closer week by week.

0:25:13 > 0:25:15And it was a message designed not just for the Dacians

0:25:15 > 0:25:17on the other side of the Danube,

0:25:17 > 0:25:20but for people all over the Empire and beyond.

0:25:20 > 0:25:23This told people that no mountain was too high,

0:25:23 > 0:25:25no river was too wide.

0:25:25 > 0:25:27Rome would spend any amount of money

0:25:27 > 0:25:30and deploy any number of soldiers to enforce its domination.

0:25:30 > 0:25:35And by building the longest bridge on the planet here on the Danube,

0:25:35 > 0:25:39Rome was laying claim to mastery of the known world.

0:25:48 > 0:25:51'Once across the river, it's believed that the main contingent

0:25:51 > 0:25:57'of the Roman Army, led by their all-conquering Emperor, Trajan,

0:25:57 > 0:26:01'hacked and killed its way up the Jiu Valley,

0:26:01 > 0:26:03'heading north,

0:26:03 > 0:26:08'towards the barbarians' capital city, Sarmizegetusa.

0:26:08 > 0:26:11'Or Sarmi for short.'

0:26:12 > 0:26:15Sarah, I'm dying here. This car is tiny, I'm getting cramp.

0:26:15 > 0:26:19Dan, you've got to stop complaining. We've got a long way to go.

0:26:19 > 0:26:22- That's tough love, man. - That's what you're getting from me.

0:26:25 > 0:26:30'King Decabulus and his warriors were finally defeated here at Sarmi.

0:26:32 > 0:26:35'Archaeologists believe after the war was over,

0:26:35 > 0:26:39'the Romans suppressed outbreaks of sporadic violence

0:26:39 > 0:26:41'with an occupying army.

0:26:41 > 0:26:44'But how they achieved this isn't known.

0:26:46 > 0:26:50'There could be clues buried beneath the undergrowth.

0:26:53 > 0:26:55'But there's a problem.

0:26:57 > 0:27:01'The whole area is completely carpeted in thick forest.

0:27:02 > 0:27:06'And Sarah's satellites can't see through trees.

0:27:07 > 0:27:11'Fortunately, all is not lost.

0:27:22 > 0:27:25'This is new for Sarah.

0:27:25 > 0:27:26'It's called LIDAR.

0:27:26 > 0:27:29'A revolutionary technique used by the military

0:27:29 > 0:27:33'to locate enemy targets in dense undergrowth.

0:27:35 > 0:27:38'Here, she's looking for walls, ditches,

0:27:38 > 0:27:42'anything that might shed light on how Rome kept the peace

0:27:42 > 0:27:44'once the war was over.

0:27:50 > 0:27:53'Rather than satellites, this involves an aeroplane,

0:27:53 > 0:27:57'which fires up to 100,000 laser beams every second

0:27:57 > 0:28:00'into the forest beneath.

0:28:00 > 0:28:03'While the first beams hit the treetops,

0:28:03 > 0:28:07'the last ones strike the forest floor.

0:28:07 > 0:28:10'So, by removing that first pulse survey,

0:28:10 > 0:28:14'scientists effectively remove the trees,

0:28:14 > 0:28:18'revealing anything which might be hidden beneath.'

0:28:21 > 0:28:23OK, Dan, here we are.

0:28:23 > 0:28:29You're looking to the central part of the site of Sarmizegetusa.

0:28:29 > 0:28:34'Dr Gelu Florea is head of archaeology at Cluj University.

0:28:34 > 0:28:37'He has spent 26 years investigating Sarmi

0:28:37 > 0:28:41'and is the number one world expert on the site.

0:28:44 > 0:28:46'Having surveyed the whole area,

0:28:46 > 0:28:50'it's time for Sarah to show Gelu the results.

0:28:50 > 0:28:53'And he's in for a big surprise.'

0:28:54 > 0:28:58Here we have a visual satellite image of Sarmi.

0:28:58 > 0:29:00As you know far better than we do,

0:29:00 > 0:29:03the area is very densely covered in trees

0:29:03 > 0:29:06and unfortunately right now with satellite imagery

0:29:06 > 0:29:08we can't see through trees.

0:29:08 > 0:29:11So we used a new technology called LIDAR,

0:29:11 > 0:29:13which is flown from an aeroplane

0:29:13 > 0:29:16and sends down thousands of pulses of beams of light

0:29:16 > 0:29:18and you can literally use that to peel away

0:29:18 > 0:29:20the layers of vegetation.

0:29:20 > 0:29:23And this is what we have.

0:29:25 > 0:29:29It's beautiful. It's amazing.

0:29:29 > 0:29:31I'll zoom in a little bit.

0:29:31 > 0:29:33So what are we seeing here? Those lines are incredible.

0:29:33 > 0:29:36It's a huge rampart, I think.

0:29:36 > 0:29:39A rampart-like feature...

0:29:41 > 0:29:44..that we never knew until now.

0:29:45 > 0:29:47It's got that shape and everything.

0:29:47 > 0:29:51It...it's beautiful. It's amazing, as a matter of fact.

0:29:51 > 0:29:53You can, I mean, it does seem pretty clear,

0:29:53 > 0:29:55not as clear here but it runs there.

0:29:55 > 0:30:01No, it's absolutely clear on this side, on this side also, and here.

0:30:01 > 0:30:05'What Sarah has discovered is completely new to Gelu.

0:30:06 > 0:30:10'According to conventional thinking, when Sarmi fell,

0:30:10 > 0:30:14'the Romans left behind a garrison of around 500 men,

0:30:14 > 0:30:17'to hold the area and make it safe.

0:30:18 > 0:30:20'But archaeologists have puzzled

0:30:20 > 0:30:24'over how that could have been achieved with so few soldiers.

0:30:26 > 0:30:30'It now looks like a massive man-made embankment

0:30:30 > 0:30:32'enclosed the whole area,

0:30:32 > 0:30:36'offering the mouth-watering possibility of fresh evidence

0:30:36 > 0:30:39'into the extent of the Roman occupation.

0:30:39 > 0:30:44'But we won't know the find is Roman until we see it on the ground.

0:30:57 > 0:31:01'We're setting off on a long trek through deep forest.

0:31:04 > 0:31:11'It's rough country, and our guides are taking no chances.

0:31:15 > 0:31:18'We're not going to make it before nightfall,

0:31:18 > 0:31:21'and Transylvania is the last place

0:31:21 > 0:31:24'you want to be walking about after dark.'

0:31:24 > 0:31:25What a nice campsite.

0:31:26 > 0:31:28- Hello there.- Hello.

0:31:35 > 0:31:37- Want some bread? - Bread would be great, thank you.

0:31:37 > 0:31:39Want a piece?

0:31:39 > 0:31:41- Bread?- No, thanks.

0:31:41 > 0:31:45Is there anything in kind of local folklore

0:31:45 > 0:31:48connecting people here to the Romans?

0:31:48 > 0:31:52Of course we say that looking at the ear lobe,

0:31:52 > 0:31:54the ones who have a long ear lobe would be Romans,

0:31:54 > 0:31:57and the ones who have small ones are Dacian.

0:31:57 > 0:31:58Let's see what you've got?

0:31:58 > 0:32:00Roman. Big emperor.

0:32:00 > 0:32:03He has a long ear lobe, Roman.

0:32:03 > 0:32:04What have I got?

0:32:04 > 0:32:07You are certainly Dacian.

0:32:07 > 0:32:11- I think I'm a Roman princess, that's for sure.- You wish.

0:32:11 > 0:32:14What do kids learn about the Romans in school?

0:32:14 > 0:32:16Are they invaders, are they evil?

0:32:16 > 0:32:19Or are they the founders of Romania?

0:32:19 > 0:32:25No, in history books, Trajan and Decebalus, the leaders of the two nations,

0:32:25 > 0:32:28they are the fathers of our nation,

0:32:28 > 0:32:30so Trajan more important than Decapolis.

0:32:30 > 0:32:34Earlier today I saw Jan was carrying a gun.

0:32:34 > 0:32:36Why was he carrying a gun?

0:32:36 > 0:32:38For bears. Why else?

0:32:53 > 0:32:57'The following day the trek continues into the heart of an ancient forest.

0:33:00 > 0:33:03'This is the original wild wood.

0:33:08 > 0:33:11'Eventually we find proof on the ground

0:33:11 > 0:33:13'that Sarah's find is indeed Roman.

0:33:15 > 0:33:17'This is the evidence we have been seeking.'

0:33:21 > 0:33:24I think this is the structure that we saw

0:33:24 > 0:33:27- already on the on the photograph. - It's very clear.

0:33:27 > 0:33:29You can see it stretching off right the way down through,

0:33:29 > 0:33:32it looks like a ditch and then a bank here.

0:33:32 > 0:33:33What would this have been?

0:33:33 > 0:33:37I think it's clearly an embankment of ramparts and that's why I think

0:33:37 > 0:33:42it's part of a defensive structure. A Roman temporary camp.

0:33:42 > 0:33:47What phase of Roman occupation do you think this was built in?

0:33:47 > 0:33:51Well, it probably belongs to the Roman garrison

0:33:51 > 0:33:55that was left here after the war.

0:33:55 > 0:33:58I can't think of another purpose than to pacify the area,

0:33:58 > 0:34:03to prevent any other skirmishes, to prevent a regrouping of forces

0:34:03 > 0:34:07around these sacred places of the Dacians and so on.

0:34:07 > 0:34:10So this is, they've won the war, now they're trying to win the peace?

0:34:10 > 0:34:12Yes.

0:34:16 > 0:34:18Sarah has finally found something.

0:34:18 > 0:34:21And it's helping to rewrite history.

0:34:24 > 0:34:29The 500-man Roman garrison was just part of a huge military camp...

0:34:33 > 0:34:37..with enough space for a further 8,000 troops.

0:34:39 > 0:34:44It shows for the first time how Rome really pacified the area.

0:34:49 > 0:34:51Investing large amounts of troops

0:34:51 > 0:34:53and thinking long term.

0:34:55 > 0:34:59It wasn't enough to simply slaughter the Dacians and then leave.

0:34:59 > 0:35:04To remove the menace, whole swathes of land had to be first made safe

0:35:04 > 0:35:07and then incorporated into the Empire.

0:35:07 > 0:35:12Imperial policy across the entire Roman world.

0:35:13 > 0:35:17Dacia is just a terrifying example of just how the Roman Empire

0:35:17 > 0:35:20invaded and occupied new territory.

0:35:20 > 0:35:21When the Romans wanted to,

0:35:21 > 0:35:25they could bring vast and ruthless military force to bear.

0:35:25 > 0:35:28They invaded Dacia, they destroyed its army,

0:35:28 > 0:35:30they wiped out its leadership

0:35:30 > 0:35:35and then they set about the long and arduous task of pacification.

0:35:35 > 0:35:38They hunted down insurgents, guerrilla fighters.

0:35:38 > 0:35:41They destroyed religious sites like this,

0:35:41 > 0:35:45anything that could provide the focus for anti-Roman resistance.

0:35:46 > 0:35:48When you come here, you realise,

0:35:48 > 0:35:51for all the wonderful art and architecture

0:35:51 > 0:35:52that the Romans produced,

0:35:52 > 0:35:57at its root, Rome was a brutal military super power.

0:35:57 > 0:36:01And that was a fundamental reason for its supremacy.

0:36:05 > 0:36:10Sarah is starting to have success. But the good news doesn't end there.

0:36:10 > 0:36:14After months of searching, she thinks she's finally

0:36:14 > 0:36:17had a breakthrough with the satellites too.

0:36:17 > 0:36:20She thinks she's found something back in Italy

0:36:20 > 0:36:24that, if true, could be groundbreaking.

0:36:29 > 0:36:34Let's take another look at Portus, the great lost harbour of Rome.

0:36:36 > 0:36:40Understanding how it worked might give us a new insight

0:36:40 > 0:36:43into how the Roman Empire as a whole operated.

0:36:45 > 0:36:48This is what archaeologists think happened.

0:36:52 > 0:36:55Ships would crowd into the big basins...

0:36:59 > 0:37:02..their cargo unloaded onto smaller boats...

0:37:07 > 0:37:11..which was then moved by canal to the River Tiber,

0:37:11 > 0:37:16and onward, along to the river, to Rome.

0:37:22 > 0:37:25But there's a big hole in this theory.

0:37:25 > 0:37:28With hundreds of ships on the water at any one time,

0:37:28 > 0:37:32there must have been major bottlenecks,

0:37:32 > 0:37:34crippling the whole transport network.

0:37:36 > 0:37:40It's something that has puzzled archaeologists for decades.

0:37:41 > 0:37:43Back in her lab in Italy,

0:37:43 > 0:37:47Sarah thinks she may have found the answer.

0:37:47 > 0:37:50So I'd like to show you an interesting thing that showed up

0:37:50 > 0:37:53on the east bank of the Tiber.

0:37:53 > 0:37:58It's about 280 metres long, about five metres wide.

0:37:58 > 0:38:03Running slightly southwest by northeast.

0:38:03 > 0:38:06You can see it running along just there.

0:38:06 > 0:38:08Ah, now that's really interesting,

0:38:08 > 0:38:12because that looks to me like it might be a canal.

0:38:12 > 0:38:16Although, I must say, it's different to the other ones we found.

0:38:16 > 0:38:18How was that different?

0:38:18 > 0:38:21Well, all the other canals we have found to date

0:38:21 > 0:38:24have been on the west side of the Tiber, close to the port...

0:38:24 > 0:38:25Portus.

0:38:25 > 0:38:28This canal is on the east side of the Tiber

0:38:28 > 0:38:32and, perhaps more significantly, it's going in the direction of Rome.

0:38:32 > 0:38:35What does it mean, that it's just heading off towards Rome?

0:38:35 > 0:38:39For me, the significance is quite straightforward.

0:38:39 > 0:38:44The fact that you have a new canal here suggests to me

0:38:44 > 0:38:46that river barges may have avoided

0:38:46 > 0:38:48this rather longer route up the Tiber

0:38:48 > 0:38:51by going more directly to Rome.

0:38:51 > 0:38:54And indeed, that helps us better understand

0:38:54 > 0:38:56how the port system as a whole worked.

0:38:56 > 0:38:58So, that's fantastic, well done.

0:39:03 > 0:39:06To test whether the new canal is actually there

0:39:06 > 0:39:08buried beneath tonnes of earth,

0:39:08 > 0:39:11Simon and his team visit the site.

0:39:16 > 0:39:21And the results of a geophysical survey are highly promising.

0:39:21 > 0:39:25It looks like Sarah is right.

0:39:27 > 0:39:31For a really eminent archaeologist like Simon who, you know,

0:39:31 > 0:39:35has devoted so much of his career to working at Portus,

0:39:35 > 0:39:39you know, seeing him get so excited about the science and be so

0:39:39 > 0:39:44willing to not only embrace it, but test it on the ground and

0:39:44 > 0:39:48think about the findings in terms of his long term research plans

0:39:48 > 0:39:51for a site - that's awesome!

0:39:56 > 0:40:00It's great to have this confirmation, it's really exciting, but for me

0:40:00 > 0:40:04what's even more exciting is it's really helping to show just how far

0:40:04 > 0:40:06the technology has come.

0:40:07 > 0:40:10I feel like that's given me a lot of confidence.

0:40:10 > 0:40:13I just absolutely cannot wait for what's next.

0:40:21 > 0:40:23Sarah's satellites are helping to show how

0:40:23 > 0:40:28this astonishing harbour landscape may actually have worked.

0:40:29 > 0:40:31An inadequate transport system

0:40:31 > 0:40:34could have left the people of Rome starving.

0:40:34 > 0:40:38Grain, in particular, had to be kept dry

0:40:38 > 0:40:41so the faster it could be moved, the better.

0:40:42 > 0:40:45And this is how they might have achieved that.

0:40:47 > 0:40:52Boats didn't have to travel all the way up the Tiber River,

0:40:52 > 0:40:56they could go straight to Rome by Sarah's canal.

0:41:00 > 0:41:03It's also helping me answer the bigger question

0:41:03 > 0:41:06of how Rome kept control of its vast Empire.

0:41:08 > 0:41:11We associate canals with the Industrial Revolution

0:41:11 > 0:41:14but the Romans were building them 2000 years ago

0:41:14 > 0:41:19and not just in Italy, but in Britain and France

0:41:19 > 0:41:23and like roads they played a key role in Rome's success.

0:41:23 > 0:41:29Portus is clearly an engineering marvel and I am just blown away

0:41:29 > 0:41:32at the Roman's ability to build roads and infrastructure,

0:41:32 > 0:41:36to dig out harbours, just to get things done.

0:41:36 > 0:41:39And it's also taught me a huge amount about how the Romans

0:41:39 > 0:41:40controlled their empire.

0:41:40 > 0:41:44Because the Romans are famous for being soldiers but clearly

0:41:44 > 0:41:47they are just as impressive as engineers.

0:41:47 > 0:41:51By creating this infrastructure, by building ports,

0:41:51 > 0:41:54by establishing shipping lanes and building roads,

0:41:54 > 0:41:56they're shrinking their world,

0:41:56 > 0:42:00they're bringing their provinces closer to Rome

0:42:00 > 0:42:04and making it easier to control them.

0:42:05 > 0:42:10Having finally got the satellites to deliver, it's game on.

0:42:12 > 0:42:15With such a vast area to control,

0:42:15 > 0:42:19Rome's military options were always going to be limited.

0:42:19 > 0:42:23A whole range of tactics were needed to stay in charge.

0:42:25 > 0:42:29But current thinking is incomplete.

0:42:29 > 0:42:32Sarah's challenge now is to fill in the gaps...

0:42:33 > 0:42:35..right across the Empire.

0:42:52 > 0:42:53'Arabia.

0:42:59 > 0:43:00'Exotic.

0:43:02 > 0:43:03'Sophisticated.

0:43:06 > 0:43:07'A land of adventure...

0:43:10 > 0:43:12'..and opportunity.

0:43:20 > 0:43:24We've travelled over 1,000 miles across the Mediterranean,

0:43:24 > 0:43:28to what was the easternmost fringe of the Roman Empire,

0:43:28 > 0:43:30modern-day Jordan.

0:43:35 > 0:43:38Coming here is a chance to see something completely different

0:43:38 > 0:43:41to the killing fields of northern Europe.

0:43:44 > 0:43:49Amazingly, the Romans seem to have conquered this entire territory,

0:43:49 > 0:43:51then kept it under control,

0:43:51 > 0:43:55apparently without spilling a single drop of blood.

0:44:01 > 0:44:04Our mission is to find out how.

0:44:09 > 0:44:11Right, Dan. I want to show you something.

0:44:11 > 0:44:14Let me pinch in a little bit here. Can you see that there?

0:44:15 > 0:44:20- Yeah, rectangular? - Yeah, it looks like a building.

0:44:20 > 0:44:23And you think that might be Roman?

0:44:23 > 0:44:26Hopefully. Hopefully, it's Roman. That's what it looks like.

0:44:26 > 0:44:28And it's never been discovered before?

0:44:28 > 0:44:31As far as I know, it's a completely new structure.

0:44:31 > 0:44:34Sarah, there is no end to your skills. That's very cool.

0:44:34 > 0:44:36I'm pretty excited about it.

0:44:47 > 0:44:51Sarah thinks she's made a brand-new discovery

0:44:51 > 0:44:53on the outskirts of an ancient city.

0:44:55 > 0:44:56But not just any old city.

0:45:00 > 0:45:02'It is one of the most beautiful places on Earth...

0:45:06 > 0:45:09'..the rose-pink city of Petra.'

0:45:19 > 0:45:21I always wondered whether I'd come back here.

0:45:21 > 0:45:24It's a very special place for me, cos I came here with my mum and dad

0:45:24 > 0:45:27when I was a kid and our whole family walked through

0:45:27 > 0:45:30that narrow dry river bed and we came out, I always remember it,

0:45:30 > 0:45:32we came out into that open space

0:45:32 > 0:45:35and we saw the incredible building in front of us.

0:45:36 > 0:45:38I think that was really the moment

0:45:38 > 0:45:40that really fired my interest in history.

0:45:42 > 0:45:47Seeing these vast buildings hacked into the living rock.

0:45:47 > 0:45:50It's like nowhere else on earth.

0:45:58 > 0:46:00But enough reminiscing.

0:46:00 > 0:46:02It's time to get back on the job.

0:46:02 > 0:46:07And look at why Rome was interested in these lands in the first place.

0:46:11 > 0:46:14Before the Roman takeover, Petra was the capital city

0:46:14 > 0:46:17of the great kingdom of Nabataea...

0:46:18 > 0:46:21..whose merchants had grown rich

0:46:21 > 0:46:26controlling the important trade routes from the Red Sea to Syria.

0:46:28 > 0:46:34It was a massive money spinner and Rome wanted a slice of the action -

0:46:34 > 0:46:37in the form of taxes and tariffs.

0:46:39 > 0:46:42But whereas invasion would normally lead to resistance,

0:46:42 > 0:46:46here the opposite seems to have happened.

0:46:46 > 0:46:49And I think the reason may be partly cultural.

0:46:54 > 0:46:58Unlike the so-called barbarians, the people here in the Middle East

0:46:58 > 0:47:02were literate and sophisticated.

0:47:02 > 0:47:05They lived in cities for a start.

0:47:05 > 0:47:09The sort of people the Romans felt they could negotiate with.

0:47:14 > 0:47:17To find out what the Romans had to trade,

0:47:17 > 0:47:20we are off to visit their fort at Azraq

0:47:20 > 0:47:22which guarded the trade routes.

0:47:24 > 0:47:29'Strong, impregnable and built of solid stone.'

0:47:29 > 0:47:32OK, you leave these doors to me, Sarah. Here we go.

0:47:32 > 0:47:34'Including the doors.'

0:47:34 > 0:47:38- Can I have a hand? - You need Cambridge woman, Dan.

0:47:38 > 0:47:39HE GROANS WITH EFFORT

0:47:39 > 0:47:41SHE LAUGHS

0:47:41 > 0:47:43HE SIGHS WITH RELIEF

0:47:43 > 0:47:45That is ridiculous.

0:47:48 > 0:47:49Before the Romans arrived here,

0:47:49 > 0:47:54the Middle East had been the setting for conflict and instability

0:47:54 > 0:47:56since the very beginning of recorded time.

0:47:56 > 0:48:00This is where empires and civilisations clashed.

0:48:00 > 0:48:02You got people like the Seleucids to the north,

0:48:02 > 0:48:05the Judeans and the Egyptians out there to the west

0:48:05 > 0:48:07and Mesopotamians to the east

0:48:07 > 0:48:11and, of course, the fierce desert tribesmen to the south.

0:48:11 > 0:48:14The result was constant violence.

0:48:14 > 0:48:18So, when the Romans arrived, they bring peace and security.

0:48:18 > 0:48:22And it doesn't even take that big a military force to achieve it.

0:48:28 > 0:48:33This happened gradually following the Roman takeover.

0:48:33 > 0:48:36But it looks like a guarantee of peace may have been enough

0:48:36 > 0:48:40to win the locals over without waging war.

0:48:40 > 0:48:43Because peace would bring prosperity.

0:48:45 > 0:48:49It's a theory that archaeologist Dr Chris Tuttle believes.

0:48:49 > 0:48:52But despite being one of the world's leading lights

0:48:52 > 0:48:55on Roman Arabia, he has yet to find the proof.

0:48:58 > 0:49:00That's because, after 2,000 years,

0:49:00 > 0:49:04evidence of widespread abundance under Roman rule

0:49:04 > 0:49:06is almost impossible to come by.

0:49:08 > 0:49:12But with the aid of state-of-the-art satellite technology,

0:49:12 > 0:49:15all that could be about to change.

0:49:15 > 0:49:18I've been surveying an area in the countryside around Petra,

0:49:18 > 0:49:21about ten square kilometres.

0:49:21 > 0:49:23Do you see right here?

0:49:23 > 0:49:27There are about 60 features that have appeared

0:49:27 > 0:49:31- which show up in these red circles.- OK. Wow.

0:49:31 > 0:49:35This is really incredible. I mean, there's so much stuff out here

0:49:35 > 0:49:37that you're finding in these satellite images.

0:49:37 > 0:49:41Based on what I know of this area, this is probably

0:49:41 > 0:49:45farmsteads, hamlets, possibly some watchtowers,

0:49:45 > 0:49:49maybe these are agricultural water management systems.

0:49:49 > 0:49:53All in all, really suggesting a landscape of abundance,

0:49:53 > 0:49:55not just inside Petra but outside as well.

0:49:55 > 0:49:58Yeah, but what really interested me, Chris,

0:49:58 > 0:50:00was this particular feature right there.

0:50:00 > 0:50:05Let me zoom in a little bit more. You can see it pretty clearly here.

0:50:05 > 0:50:07Wow, that's very large.

0:50:07 > 0:50:12So this, out of all the features that appeared on the satellite imagery,

0:50:12 > 0:50:14really kind of grabbed me the most.

0:50:14 > 0:50:17Well, we should go take a look at it and see if it

0:50:17 > 0:50:19has occupation during the Roman period.

0:50:19 > 0:50:21- I'd like to see it. - All right, let's go.

0:50:23 > 0:50:27We're heading into a countryside that appears barren

0:50:27 > 0:50:31to look for evidence that it flourished under the Romans.

0:50:36 > 0:50:40It's a confusing landscape of sand and rubble.

0:50:40 > 0:50:43But with the aid of satellite technology,

0:50:43 > 0:50:46Sarah can take us straight to the spot.

0:50:54 > 0:50:57Wow, you guys. This is a really big site and very exciting.

0:50:57 > 0:50:59So what do you think it might have been?

0:50:59 > 0:51:01Like a domestic or a fort or something like that?

0:51:01 > 0:51:04Well, actually it's most likely related to farming.

0:51:04 > 0:51:07And it's very big so we're dealing with something like a...

0:51:07 > 0:51:11It's a big farming system, this is probably the farm estate house.

0:51:11 > 0:51:14What do you think the time period might be for this site?

0:51:14 > 0:51:17Hard to tell without finding something to see if we can date it.

0:51:17 > 0:51:19- Why don't we go take a look? - Let's go.

0:51:19 > 0:51:21OK, what are we looking for, archaeologists?

0:51:21 > 0:51:22Pottery!

0:51:22 > 0:51:24- DAN LAUGHS - Ah, OK.

0:51:31 > 0:51:34Ever since I've started hanging out with Sarah,

0:51:34 > 0:51:35I've had a crick in my neck.

0:51:35 > 0:51:37She spends the whole time staring at the ground,

0:51:37 > 0:51:39looking for smashed old bits of pottery,

0:51:39 > 0:51:43which she then claims, like this one here,

0:51:43 > 0:51:46which she claims that she can tell the date from.

0:51:46 > 0:51:47I mean, you've got to be kidding me.

0:51:47 > 0:51:50I think that's all they do in archaeology school

0:51:50 > 0:51:53for three years is just look at old bits of pottery.

0:51:53 > 0:51:56Historians, we like a bit of papyrus or a scroll!

0:51:56 > 0:51:57That tells you stuff.

0:51:58 > 0:52:01OK, let's take a look at what we found.

0:52:01 > 0:52:04OK, a lot of stuff that we really can't tell much about.

0:52:04 > 0:52:06Those are really nice.

0:52:06 > 0:52:10Sorry, Dan, no. But this one we can take a look at.

0:52:10 > 0:52:14Ah, Sarah, these are perfect. Excellent, excellent.

0:52:14 > 0:52:19Well, we definitely have pottery here indicating that this farm

0:52:19 > 0:52:21was in use during the Roman period.

0:52:21 > 0:52:24But looking at the size of it, we can see that there's even

0:52:24 > 0:52:26expansion that's probably taking place at this time.

0:52:26 > 0:52:29From the work you're doing in Petra and from the results that are

0:52:29 > 0:52:32coming up on Sarah's satellites, this area seems to be flourishing.

0:52:32 > 0:52:35I couldn't agree more, I think the satellite technology

0:52:35 > 0:52:38in particular is really going to help us get a better understanding

0:52:38 > 0:52:42of this time period here in Petra and in its surrounding environs.

0:52:42 > 0:52:46You've revealed a lot of potential sites

0:52:46 > 0:52:49that will help us understand this period in history a lot more.

0:52:55 > 0:52:59Rome was mainly an agricultural society -

0:52:59 > 0:53:02the majority of its citizens were farmers.

0:53:04 > 0:53:07And we now know that thousands of them came from here -

0:53:07 > 0:53:09Arabia.

0:53:11 > 0:53:13Sarah's satellites show a countryside

0:53:13 > 0:53:20brimming with farmsteads, growing olives, cereals and fruit trees -

0:53:20 > 0:53:23a flourishing Arabia under Roman rule.

0:53:27 > 0:53:32'It helps us understand how Rome ruled without resorting to violence.

0:53:34 > 0:53:38'Rome brought peace and prosperity

0:53:38 > 0:53:41'and a rich people are less likely to resist.

0:53:44 > 0:53:47This leg of the journey has really helped me

0:53:47 > 0:53:49to get some answers to my original question.

0:53:49 > 0:53:52Just how did Rome manage to rule over such a vast empire

0:53:52 > 0:53:55stretching here from the deserts of Arabia

0:53:55 > 0:53:57right the way across to the west coast of Britain

0:53:57 > 0:54:00with actually a relatively small number of full-time

0:54:00 > 0:54:03professional legionary soldiers.

0:54:03 > 0:54:05I think coming here and seeing how it all worked

0:54:05 > 0:54:07has made me think about cooperation.

0:54:07 > 0:54:11I think the Nabateans and the Romans that occupied Petra

0:54:11 > 0:54:13both realised pretty quickly

0:54:13 > 0:54:18they could achieve a lot more if they cooperated. Trade flourished

0:54:18 > 0:54:21because they could now export from here right across the Empire

0:54:21 > 0:54:23and import goods as well.

0:54:23 > 0:54:26Also, the Nabateans realised they didn't have to spend money on a

0:54:26 > 0:54:29standing army any more because the Romans would look after

0:54:29 > 0:54:33external security. It was all very different in northern Europe.

0:54:33 > 0:54:35There the tribes that the Romans dismissed as barbarians were

0:54:35 > 0:54:38less interested in trade and interacting with the Roman Empire.

0:54:38 > 0:54:42They didn't want to go to the theatre. They had to be destroyed,

0:54:42 > 0:54:44one after the other, with overwhelming military force.

0:54:44 > 0:54:48Here in Petra, people saw the benefits of working with the Romans.

0:54:48 > 0:54:51I don't think the Romans needed to send armies

0:54:51 > 0:54:53through these streets keeping the Nabateans loyal.

0:54:53 > 0:54:56The people here were happy to be Roman.

0:55:02 > 0:55:05It's time to return to Portus,

0:55:05 > 0:55:07the great lost harbour.

0:55:09 > 0:55:13Because creating prosperity, with or without warfare,

0:55:13 > 0:55:16would never be enough to rule an entire Empire.

0:55:19 > 0:55:22There is more still to learn.

0:55:23 > 0:55:26The power of mind games.

0:55:32 > 0:55:35Back in her lab in Italy, Sarah has made

0:55:35 > 0:55:38an astonishing and completely unexpected discovery.

0:55:40 > 0:55:42So, in this particular satellite image,

0:55:42 > 0:55:45you can see we're to the northeast of the Trajanic Basin.

0:55:45 > 0:55:47And we're looking at fields.

0:55:47 > 0:55:50You know, partially cultivated, nothing's apparent in them.

0:55:50 > 0:55:55So, I looked at a satellite image from a different kind of year,

0:55:55 > 0:55:59using assorted computer logarithms, and this is what I found.

0:56:00 > 0:56:04- Oh, good heavens.- Wow! - That really is interesting.

0:56:04 > 0:56:07Simon, what is that?

0:56:07 > 0:56:09It looks to me like an amphitheatre.

0:56:09 > 0:56:12I mean, you can see by the oval shape

0:56:12 > 0:56:15and the fact that the sides are slightly squeezed

0:56:15 > 0:56:18that it's an amphitheatre-shaped building.

0:56:18 > 0:56:20No doubt about it at all.

0:56:20 > 0:56:25What would the significance be of a possible amphitheatre located here?

0:56:25 > 0:56:29Well, if it was an amphitheatre, it would be, I think, very significant.

0:56:29 > 0:56:32I mean, one has to remember, first of all,

0:56:32 > 0:56:35that amphitheatres are amongst the most iconic

0:56:35 > 0:56:38of all Roman public buildings.

0:56:38 > 0:56:41They are very large, they're very prominent,

0:56:41 > 0:56:43they consist of banks of seating

0:56:43 > 0:56:46arranged around the edge of the building,

0:56:46 > 0:56:49focusing in upon an arena.

0:56:49 > 0:56:53And they were used for a range of activities.

0:56:53 > 0:56:56One has to think of public meetings

0:56:56 > 0:57:00or mock sea battles or animal baiting.

0:57:00 > 0:57:03But, of course, the most iconic activity of all

0:57:03 > 0:57:05would have been gladiatorial combat.

0:57:08 > 0:57:11The potential of this for our understanding of the port

0:57:11 > 0:57:14is very significant, so, you know, well done, Sarah.

0:57:17 > 0:57:20Amphitheatres were major status symbols.

0:57:20 > 0:57:22And Portus may have had one.

0:57:22 > 0:57:26There is only one way to tell for certain and that's to dig.

0:57:26 > 0:57:29That could take months, even years.

0:57:29 > 0:57:32Even simple geophysics here is not straightforward

0:57:32 > 0:57:36because this land is privately owned.

0:57:36 > 0:57:40But the satellite imagery is startlingly clear.

0:57:40 > 0:57:43And to find out what this might mean for Portus,

0:57:43 > 0:57:46there is only one place to visit.

0:57:46 > 0:57:49A larger version of Sarah's find,

0:57:49 > 0:57:54and the most magnificent building in the whole of Rome -

0:57:54 > 0:57:56the mighty Coliseum.

0:57:58 > 0:58:0250,000 people would have packed into here.

0:58:02 > 0:58:04The mob - tumultuous, riotous,

0:58:04 > 0:58:06capable of bringing down the government.

0:58:06 > 0:58:11Control this mob, the people of Rome, and you control the city.

0:58:11 > 0:58:14You control the city, then you control the Roman world.

0:58:19 > 0:58:21For me, amphitheatres represent a coming together

0:58:21 > 0:58:23of perfect order on the one hand...

0:58:25 > 0:58:27..and terrible violence on the other.

0:58:29 > 0:58:34A powerful combination which helped bind the Empire together.

0:58:37 > 0:58:40Seating was strictly controlled.

0:58:40 > 0:58:42The rich and powerful sat at the front.

0:58:45 > 0:58:48Poor people and women, at the back.

0:58:53 > 0:58:56It was a microcosm of Roman society,

0:58:56 > 0:59:00brought together to watch a spectacle of extreme brutality.

0:59:03 > 0:59:06But to what end?

0:59:08 > 0:59:10What was going on here in the arena of the Coliseum

0:59:10 > 0:59:13and in amphitheatres right across the Empire

0:59:13 > 0:59:18was a giant communal celebration of conquest.

0:59:18 > 0:59:22Slaves were dragged in here from defeated enemy armies

0:59:22 > 0:59:25and from occupied provinces and then slaughtered

0:59:25 > 0:59:32again and again and again in huge re-enactments of Roman victories.

0:59:32 > 0:59:36The people watching these spectacles would have been left in no doubt

0:59:36 > 0:59:39that Rome was utterly dominant.

0:59:41 > 0:59:45And nowhere was it more important to assert imperial authority

0:59:45 > 0:59:50than Portus, the gateway to the Empire.

0:59:50 > 0:59:54It looks like close to its heart there was an amphitheatre,

0:59:54 > 0:59:59the very embodiment of Roman pomp, swagger and showmanship.

1:00:06 > 1:00:09'A building designed to send subliminal messages

1:00:09 > 1:00:14'reverberating right across the Empire.

1:00:18 > 1:00:22'Back in Portus, it's an idea Simon Keay is keen to explore.

1:00:25 > 1:00:29'For him, the whole harbour worked like some gigantic piece of theatre.

1:00:32 > 1:00:34'The psychological impact of its buildings

1:00:34 > 1:00:37'every bit as powerful as their practical function.

1:00:40 > 1:00:44'His team are busy excavating a part of the harbour

1:00:44 > 1:00:46'which makes the point perfectly.'

1:00:46 > 1:00:49So, Simon, what are we looking at here?

1:00:49 > 1:00:52Well, we are right in the centre of the port and in front of us

1:00:52 > 1:00:57we have a building that's 200 metres long and 14 metres high,

1:00:57 > 1:01:01just dominating the basin as you approached it.

1:01:01 > 1:01:05And is the ship-sheds of ancient Portus.

1:01:09 > 1:01:13These sheds would have housed warships belonging to

1:01:13 > 1:01:15a detachment of the Imperial Fleet.

1:01:15 > 1:01:18So we are talking here about an absolutely gigantic building.

1:01:18 > 1:01:21- This is on a huge scale. - It is, it's on a massive scale.

1:01:24 > 1:01:28One has to imagine you are in a ship coming from the Provinces

1:01:28 > 1:01:30and you've never seen buildings on this scale before.

1:01:30 > 1:01:33Pretty intimidating, I think.

1:01:33 > 1:01:36It's built partially functionally,

1:01:36 > 1:01:39large but also built to make you feel small

1:01:39 > 1:01:41and that's exactly what this was intended to do.

1:01:41 > 1:01:45It's amazing because you've described the port as a social phenomenon -

1:01:45 > 1:01:47they've been able to bring in all the grain -

1:01:47 > 1:01:49as an engineering marvel,

1:01:49 > 1:01:51but there's also a psychological dimension.

1:01:51 > 1:01:54The genius of it is that it's about, as you say,

1:01:54 > 1:01:57it's about trade, it's about economics

1:01:57 > 1:02:00but it's also about ideology and symbolism.

1:02:00 > 1:02:03It's very much a case of architecture being used

1:02:03 > 1:02:06as a way of trying to control people.

1:02:06 > 1:02:08It's a very remarkable complex.

1:02:09 > 1:02:13'And there is nothing to make the first-time visitor feel more

1:02:13 > 1:02:19'insignificant than a 25-foot giant dominating the centre of the port.

1:02:20 > 1:02:23There's one last thing

1:02:23 > 1:02:27and that is the long-lost statue of the Emperor Trajan.

1:02:27 > 1:02:29It must have been extraordinary.

1:02:29 > 1:02:32Trajan was a great general, of course -

1:02:32 > 1:02:35as you know, he conquered Dacia.

1:02:35 > 1:02:40He also undertook military campaigns in the Middle East.

1:02:40 > 1:02:43His qualities are summed up in this great statue,

1:02:43 > 1:02:47which just dominates by virtue of its sheer scale.

1:02:47 > 1:02:50What does that statue tell us about how he wants to be remembered?

1:02:50 > 1:02:53Emperor worship was prevalent in the Roman world.

1:02:53 > 1:02:56It played a very important role in the political process

1:02:56 > 1:03:00and, I think, to see a statue this size,

1:03:00 > 1:03:03in the context of this great harbour,

1:03:03 > 1:03:06it would really have put you in your place

1:03:06 > 1:03:10and be a reminder about the strength of Roman power.

1:03:10 > 1:03:12You'd have felt like you were in the presence of a god.

1:03:12 > 1:03:14Exactly.

1:03:26 > 1:03:31'The giant statue and the ship-sheds of ancient Portus

1:03:31 > 1:03:34'were designed to dazzle the senses.

1:03:36 > 1:03:40'Along with Sarah's fabulous new discovery, the amphitheatre.

1:03:44 > 1:03:48'Only the great lost lighthouse itself

1:03:48 > 1:03:51'was a more potent symbol of Imperial power.

1:03:53 > 1:03:56'And it was symbols more than fighting

1:03:56 > 1:03:58'that bound the Empire together.'

1:04:00 > 1:04:02Buildings like the Coliseum were

1:04:02 > 1:04:05so much more than just beautiful architecture.

1:04:05 > 1:04:08They are vital clues that tell us how Rome managed

1:04:08 > 1:04:11to maintain its grip on its Empire.

1:04:11 > 1:04:14Nowadays, people get a lot of their information through reading

1:04:14 > 1:04:16newspapers or magazines or the internet.

1:04:16 > 1:04:20But back in Roman times, a lot of people couldn't read and so symbols

1:04:20 > 1:04:25become vitally important and that's why Rome built huge statues,

1:04:25 > 1:04:28temples, triumphal arches and amphitheatres

1:04:28 > 1:04:31right across its Empire.

1:04:31 > 1:04:33Because they drive a simple message into the minds

1:04:33 > 1:04:35of anyone who sees them,

1:04:35 > 1:04:39that a civilisation that's capable of building things like this

1:04:39 > 1:04:42is a force to be reckoned with.

1:04:46 > 1:04:50'We've seen the majesty of Roman rule around their capital city...

1:04:54 > 1:04:57'..their crushing of the barbarian horde in Europe...

1:05:01 > 1:05:05'..and how they held on to power in the sophisticated east.

1:05:09 > 1:05:12'Rome's vast, sprawling Empire

1:05:12 > 1:05:16'covered 5 million square miles of land.

1:05:18 > 1:05:21'There is only one place left to look.

1:05:40 > 1:05:42'Africa.

1:05:42 > 1:05:45'It's somewhere I've always wanted to come and see for myself.

1:05:48 > 1:05:53'Because controlling these lands set Rome its greatest challenge of all.

1:05:55 > 1:05:58'And it'll be Sarah's greatest challenge

1:05:58 > 1:06:00'working out how they achieved it.

1:06:02 > 1:06:05'Crack this and we'll complete the picture.

1:06:08 > 1:06:11'We're flying to Tunis, in modern-day Tunisia,

1:06:11 > 1:06:12'to begin our task.

1:06:21 > 1:06:28'After annihilating its bitter rival, Carthage, here in 146BC,

1:06:28 > 1:06:31'Rome seized a large section of the North African coastline.

1:06:33 > 1:06:36'So far so good.

1:06:36 > 1:06:39'It met with little resistance

1:06:39 > 1:06:42'and Africa's rich, loamy soils

1:06:42 > 1:06:47'could provide Rome with the one thing it craved more than anything.'

1:06:48 > 1:06:52- Sarah, look what's in all these fields.- What's that, Dan?

1:06:52 > 1:06:55You've got to take your head out of that computer from time to time.

1:06:55 > 1:06:57THIS is what it's all about.

1:07:00 > 1:07:03You see, it's pretty green as it's early in the year.

1:07:03 > 1:07:07But we've been driving through miles and miles...

1:07:07 > 1:07:10of wheat.

1:07:10 > 1:07:13Look at that. I mean, this whole area is so fertile,

1:07:13 > 1:07:17and, of course, we're only two days journey by boat away from Portus.

1:07:17 > 1:07:21So this wheat can be in Roman bread ovens in just a matter of days.

1:07:21 > 1:07:23You know, even by 50BC,

1:07:23 > 1:07:26this area is producing 250,000 tonnes a year.

1:07:26 > 1:07:29That's more than half of Rome's annual consumption of wheat

1:07:29 > 1:07:32coming from this area. I mean, this is Rome's granary.

1:07:34 > 1:07:38'But as Rome grew, so did its appetite.

1:07:40 > 1:07:44'By the First Century AD, it was the biggest city in the world,

1:07:44 > 1:07:47'with up to a million inhabitants.

1:07:48 > 1:07:52'And without enough bread to feed all those extra hungry mouths,

1:07:52 > 1:07:54'there'd be rioting in the streets.

1:07:58 > 1:08:03'With demand for wheat now exceeding production along the African coast,

1:08:03 > 1:08:08'Rome turned its eye inland, to the central Tunisian plateau.

1:08:10 > 1:08:14'Ideal for wheat production on an industrial scale.

1:08:15 > 1:08:17'But there was a problem.'

1:08:34 > 1:08:36That's a heck of a view, Sarah.

1:08:36 > 1:08:39It's amazing just how much you can see.

1:08:39 > 1:08:43- Yeah.- It's vast. - It's a big, big space, this.

1:08:46 > 1:08:49'The plateau was nearly 17,000 square miles.

1:08:51 > 1:08:53'So once the wheat was planted,

1:08:53 > 1:08:57'how could Rome defend such a huge expanse of territory?

1:09:04 > 1:09:09'Nomadic farmers had been using this land themselves for generations

1:09:09 > 1:09:13'as summer grazing ground for their sheep and goats -

1:09:13 > 1:09:16'livestock which could eat or trample a farmer's crops

1:09:16 > 1:09:19'before they could be harvested.

1:09:20 > 1:09:24'So to safeguard Rome's food supply,

1:09:24 > 1:09:27'the pastoralists had to be stopped.

1:09:32 > 1:09:35'To control their movement and keep an eye out

1:09:35 > 1:09:37'for raiding parties from the desert,

1:09:37 > 1:09:41'a sophisticated frontier system was constructed.

1:09:41 > 1:09:43'A series of walls and ditches stretching

1:09:43 > 1:09:47'from modern-day Libya all the way to Morocco.

1:09:51 > 1:09:55'But how could Rome, with such a small professional army,

1:09:55 > 1:09:58'possibly defend a 1,500-mile-long frontier?

1:10:03 > 1:10:06'The world expert on Rome's southern frontier is Professor David Mattingly.

1:10:09 > 1:10:11'He thinks he knows the secret,

1:10:11 > 1:10:14'but there is one gaping hole in his theory.'

1:10:14 > 1:10:17- Hey, how are you?- Hello, good to see you.- Yeah, good to see you.

1:10:17 > 1:10:18It's good to be here in the desert.

1:10:18 > 1:10:20'Sarah is hoping she can help.'

1:10:20 > 1:10:23Perfect weather to find some Roman stuff.

1:10:23 > 1:10:25- Hey. Nice to meet you, David. - Lovely to see you.

1:10:28 > 1:10:32Right, so, David, I wanted to show you something

1:10:32 > 1:10:34spotted from the satellite imagery.

1:10:34 > 1:10:37I wanted to get your opinion on what you think you're looking at.

1:10:37 > 1:10:38What do you make of that?

1:10:38 > 1:10:43Wow, that's wonderful. That-that looks like a Roman fort.

1:10:43 > 1:10:45That's a very distinctive shape, isn't it?

1:10:45 > 1:10:48Is it those round corners, is that what makes you think it's a fort?

1:10:48 > 1:10:51Yes, and you know, it's got a large ditch around the outside.

1:10:51 > 1:10:54You can see some central structures within it.

1:10:54 > 1:10:57And then, I mean, this looks to me like quite a large settlement

1:10:57 > 1:11:00right around it, almost like village around it.

1:11:00 > 1:11:02How exciting is this new technology?

1:11:02 > 1:11:04You're here on the ground, what does this add?

1:11:04 > 1:11:0830 years ago, I came into this area with, you know, before GPS,

1:11:08 > 1:11:11no satellite imagery, didn't even have air photographs.

1:11:11 > 1:11:14I had some old maps and sort of 19th-century references

1:11:14 > 1:11:16to the odd site.

1:11:16 > 1:11:19And as I found some elements, the garrison that manned the frontier

1:11:19 > 1:11:23was completely missing and I've been waiting 30 years

1:11:23 > 1:11:25for the technological breakthroughs

1:11:25 > 1:11:28to be able to come back and complete the story.

1:11:31 > 1:11:35'But before we check it out on the ground, David wants to explain

1:11:35 > 1:11:39'how the frontier system might have worked with a relatively small

1:11:39 > 1:11:44'number of soldiers, acting more like border police than warriors.

1:11:48 > 1:11:50'We're on our way to see something

1:11:50 > 1:11:53'that doesn't appear in any tourist guide.'

1:11:53 > 1:11:57- Follow me but watch your footing on this.- Yeah, it's a good climb.

1:11:58 > 1:12:02'High in the Cherb mountains of southern Tunisia,

1:12:02 > 1:12:04'the Bir Umm Ali wall.'

1:12:09 > 1:12:12- So how amazing is this view? - Oh, it's incredible.

1:12:12 > 1:12:15What a view, it's extraordinary.

1:12:15 > 1:12:18This is a Roman frontier wall that's running down this slope

1:12:18 > 1:12:21and completely closing off this mountain pass.

1:12:21 > 1:12:25I like to think about this as a point of control in the landscape.

1:12:25 > 1:12:30Out there, desert landscape, little vegetation, we've got oases,

1:12:30 > 1:12:33there's some great salt flat areas, very desolate.

1:12:33 > 1:12:37Behind us, we've got rich pasture, agricultural zone,

1:12:37 > 1:12:41and what Rome was trying to do is to control the movement of people

1:12:41 > 1:12:44between the desert and that cultivated zone.

1:12:44 > 1:12:48The wall may have controlled but why not just keep them out altogether?

1:12:48 > 1:12:51If they'd tried, they would have been fighting a perpetual war

1:12:51 > 1:12:53with these desert peoples.

1:12:53 > 1:12:56This way, they incorporate them into the structure

1:12:56 > 1:12:59of the Roman Empire and they can achieve that

1:12:59 > 1:13:02with a much greater economy of force.

1:13:02 > 1:13:06This becomes a permeable frontier rather than a line at which

1:13:06 > 1:13:09you repulse those desert peoples.

1:13:12 > 1:13:15'The idea that the frontier was policed by Roman soldiers

1:13:15 > 1:13:19'acting more like customs officials than Royal Marines

1:13:19 > 1:13:21'is an interesting theory.

1:13:21 > 1:13:23'But it's only a theory.

1:13:24 > 1:13:28'Where the soldiers came from to man this isolated outpost

1:13:28 > 1:13:31'is a question David has never been able to answer.'

1:13:34 > 1:13:37Right, David, we should be getting pretty close.

1:13:37 > 1:13:39I can't see anything out there on the landscape, can you?

1:13:39 > 1:13:41Can you make anything out? Over.

1:13:41 > 1:13:44OK, I'm looking out. I can't see anything.

1:13:44 > 1:13:48Amazing empty landscape we're looking at. Over.

1:13:50 > 1:13:54'According to my GPS and satellite imagery,

1:13:54 > 1:13:57'we're about 500 metres away.'

1:13:57 > 1:13:58There's a fork in the road here,

1:13:58 > 1:14:01do you want to go right or left? We need to go...

1:14:01 > 1:14:04I think we just need to continue on ahead, according to my GPS.

1:14:04 > 1:14:09Sarah, do you think it's the mound over there on the right now?

1:14:09 > 1:14:12'We could stop and have a look. Over.'

1:14:13 > 1:14:16Copy that. Over and out.

1:14:16 > 1:14:18How are we looking? You think this is it?

1:14:18 > 1:14:22Yeah, I think that's definitely... That's definitely it.

1:14:27 > 1:14:32'Surrounding what may have been the fort is the 2,000-year-old debris

1:14:32 > 1:14:35'of a large and densely populated village.'

1:14:35 > 1:14:38Look at all this pottery in front of us.

1:14:38 > 1:14:39Yeah, we need some diagnostics.

1:14:39 > 1:14:41Whoo-hoo!

1:14:42 > 1:14:43So what can you tell from that?

1:14:43 > 1:14:48Well, that's a classic early second century Roman bowl.

1:14:48 > 1:14:50And that would normally, in this part of the world,

1:14:50 > 1:14:52at that date, go with a military site.

1:14:52 > 1:14:55So that's, I think, a pretty good confirmation of

1:14:55 > 1:14:57what we're dealing with on this site is military.

1:14:59 > 1:15:02Wow. This is the ditch, isn't it?

1:15:02 > 1:15:06- Absolutely right.- That's amazing! And this is the fort here.

1:15:08 > 1:15:11It's exactly like the satellite photo. It's brilliant, isn't it?

1:15:11 > 1:15:15Yeah, the platform of the fort just standing up here is really clear.

1:15:17 > 1:15:20- Uh-oh, somebody's been digging. - This is not good.

1:15:20 > 1:15:23Looks like we've had some local treasure hunters in action.

1:15:23 > 1:15:25Not good.

1:15:25 > 1:15:28What? Local people just looking for coins and things like that?

1:15:28 > 1:15:31Just digging holes. I guess so. Look at this, this is even bigger.

1:15:31 > 1:15:34You can actually see where the JCBs came in

1:15:34 > 1:15:38and dug out big chunks of dirt and deposited them on either side.

1:15:38 > 1:15:41The only good thing about this from our point of view is

1:15:41 > 1:15:44we can see some of the agricultural levels that this has cut through.

1:15:44 > 1:15:48There's about two metres of floor level and deposits within this.

1:15:48 > 1:15:50It shows just how long this site was running for.

1:15:50 > 1:15:53David, I can tell you're very keen to get your trowel out.

1:15:53 > 1:15:55You going to start digging straightaway?

1:15:55 > 1:15:58- Well, it is very tempting. - What are we looking at here?

1:15:58 > 1:16:02What are these...this sort of this rocky area in the middle?

1:16:02 > 1:16:04Well, from where I'm standing,

1:16:04 > 1:16:08that's just a chaos of collapsed boulders, really.

1:16:08 > 1:16:10I need, I think, some help from space.

1:16:10 > 1:16:13Right, here we go. That's what I'm here for.

1:16:13 > 1:16:16This stuff is so difficult to read on the ground sometimes

1:16:16 > 1:16:20but the satellite images really come into their own.

1:16:20 > 1:16:22Here we go, so we're standing right about there.

1:16:22 > 1:16:24You can see almost exactly where we are.

1:16:24 > 1:16:28OK, we can see the ditch very, very clearly.

1:16:28 > 1:16:31But all that rubble in the middle, actually represents

1:16:31 > 1:16:33what looks like a big square building.

1:16:33 > 1:16:36What's it like for you guys? You're archaeologists.

1:16:36 > 1:16:40This is the first time this site has been visited by archaeologists.

1:16:40 > 1:16:42It's a previously unknown Roman site.

1:16:42 > 1:16:45Well, I came here all those years ago

1:16:45 > 1:16:47looking for exactly this sort of site.

1:16:47 > 1:16:51Couldn't find it. Needle in a haystack in this valley at the time.

1:16:51 > 1:16:55But thanks to Sarah, you know, here we are.

1:16:55 > 1:16:58Well, I can tell you, David, that there's not just this one.

1:16:58 > 1:17:01There's actually up to 20 others just like it in this valley.

1:17:01 > 1:17:05I'm going to have to take that away and look for something.

1:17:05 > 1:17:09That's amazing news. That, I mean, is really an extraordinary result.

1:17:09 > 1:17:12You'll have to show me the rest of these a little later.

1:17:12 > 1:17:14We have a lot of articles to write.

1:17:14 > 1:17:18What does this now tell us about this part of the Roman frontier

1:17:18 > 1:17:21that we perhaps didn't know before? What gaps does this fill in?

1:17:21 > 1:17:22OK, let me do my sums quickly.

1:17:22 > 1:17:25In a fort like this, it's quite a small fort,

1:17:25 > 1:17:28so maybe there's 50, 100 soldiers here.

1:17:28 > 1:17:31But that settlement round about can certainly accommodate

1:17:31 > 1:17:33several hundred, maybe 1,000 people.

1:17:33 > 1:17:36And if you say there's 20 of these in the valley,

1:17:36 > 1:17:39we've got a very significant population in the valley here,

1:17:39 > 1:17:41in the Roman period.

1:17:41 > 1:17:43And what that tells us is that the frontier worked.

1:17:46 > 1:17:49'Sarah's satellites are helping to show

1:17:49 > 1:17:52'how the whole frontier system actually functioned.

1:17:54 > 1:17:57'Troops were strategically positioned along the valley

1:17:57 > 1:18:00'in a series of forts like this one,

1:18:00 > 1:18:05'and used as border police to manage the movement of people across

1:18:05 > 1:18:09'the frontier, rather than ban entry altogether and risk all-out war.

1:18:13 > 1:18:17'And we now know that all of these forts were surrounded by

1:18:17 > 1:18:21'large civilian settlements which were prosperous and stable.

1:18:22 > 1:18:26'Proving once and for all that it was a system that worked.

1:18:28 > 1:18:32'And worked well enough with a relatively small number of professional soldiers.

1:18:37 > 1:18:41'It's a triumph. And one that calls for a celebration.

1:18:41 > 1:18:45'And what could be more appropriate than an authentic Roman feast,

1:18:45 > 1:18:50'cooked in the desert, by a friendly expert, Sally Grainger.

1:18:50 > 1:18:54I've a few more quails here, straight off the barbie.

1:18:54 > 1:18:56Always room for another quail somewhere.

1:18:56 > 1:18:59How are you feeling about the high hopes we had

1:18:59 > 1:19:00for those satellite results?

1:19:00 > 1:19:03Have you seen it on the ground? Are you happy with what you've seen?

1:19:03 > 1:19:07I'm absolutely thrilled. We think we've answered every question

1:19:07 > 1:19:10and found everything there is to be found but what the satellites

1:19:10 > 1:19:14are showing us is just... There's so much more left to find.

1:19:14 > 1:19:17And I just think it's the most exciting time in history

1:19:17 > 1:19:18to be an archaeologist.

1:19:18 > 1:19:22I'll drink to that. And I'll say thank you very much, Sarah.

1:19:22 > 1:19:24- Thank you, David.- And Dan.

1:19:24 > 1:19:27And thank you very much for taking us round. Thank you for the meal.

1:19:37 > 1:19:41This trip to Tunisia has taught me so much about Roman frontiers,

1:19:41 > 1:19:43both here in North Africa and right across the Empire.

1:19:43 > 1:19:48These aren't just physical barriers, they're psychological barriers.

1:19:48 > 1:19:53They dominate the landscape like no other empire has done before.

1:19:53 > 1:19:56And I think that everybody who crossed those walls,

1:19:56 > 1:19:58whether you go through one of the gates

1:19:58 > 1:20:00or even manage to sneak over at night,

1:20:00 > 1:20:03everybody who crossed those walls would know

1:20:03 > 1:20:05they were now in Roman territory.

1:20:05 > 1:20:06And it's also been so interesting

1:20:06 > 1:20:09just how clever the Romans were as well.

1:20:09 > 1:20:13They didn't just try and seal off the borders and block everybody out.

1:20:13 > 1:20:18They were happy to let traffic through as long as it suited them.

1:20:18 > 1:20:20They even encouraged it.

1:20:20 > 1:20:22People were allowed to come through the wall,

1:20:22 > 1:20:26trade was allowed to happen, but only if it suited Rome.

1:20:35 > 1:20:38'We're back in Portus for one final look.

1:20:40 > 1:20:43'The great lost harbour is at last making sense.

1:20:45 > 1:20:48'Sarah has discovered another canal,

1:20:48 > 1:20:51'bringing new insight into how

1:20:51 > 1:20:54'this fabulous port complex actually worked.

1:20:57 > 1:21:00'She's even found an amphitheatre,

1:21:00 > 1:21:05'but the greatest prize of all has eluded her.'

1:21:05 > 1:21:08Simon, there's something else I'd like to show you

1:21:08 > 1:21:10that I think you'll find of great interest.

1:21:10 > 1:21:14So here we have the Claudian basin with the northern and southern quays.

1:21:14 > 1:21:17Based on this hypothetical location,

1:21:17 > 1:21:19I've done some preliminary imagery analysis work

1:21:19 > 1:21:21- that I'd like to show you.- OK.

1:21:30 > 1:21:33Yeah, that's interesting.

1:21:33 > 1:21:36I mean, it's...there's very clearly something there.

1:21:36 > 1:21:40I mean, I'm not entirely convinced at what it is.

1:21:40 > 1:21:44'It's the culmination of Sarah's work and effort.

1:21:44 > 1:21:47'The final piece of a dazzling great jigsaw.

1:21:47 > 1:21:50'But maybe she's got it wrong.'

1:21:50 > 1:21:54Yeah, I mean, you know, the results are, at best, ambiguous.

1:21:54 > 1:21:58There's a shape perhaps but at the very least it showed me

1:21:58 > 1:22:01that there could be potentially something there

1:22:01 > 1:22:04and it was worthwhile doing additional processing work.

1:22:04 > 1:22:09So I used a different kind of image called LIDAR.

1:22:09 > 1:22:12Actually, it's the same thing we used in Romania.

1:22:12 > 1:22:14We used different types of processing.

1:22:18 > 1:22:20And this is what showed up!

1:22:23 > 1:22:27Good heavens! Now this is a different prospect altogether!

1:22:27 > 1:22:30This is really incredible.

1:22:30 > 1:22:32Um...

1:22:32 > 1:22:36You can see very, very clearly how that massive feature

1:22:36 > 1:22:41is at an angle to the modern buildings there and also,

1:22:41 > 1:22:45it's centrally located between the north and the south quays.

1:22:45 > 1:22:47That's extraordinary.

1:22:47 > 1:22:51And the other thing is that, it's immediately to the west

1:22:51 > 1:22:56of where my Italian colleagues have been working, doing deep coring

1:22:56 > 1:22:59and finding large chunks of masonry and some geophysics.

1:22:59 > 1:23:03Um, but could I ask how big that is?

1:23:03 > 1:23:06It's about 140 metres long, and about 40 metres wide.

1:23:08 > 1:23:12Dare I say it, but this is the platform

1:23:12 > 1:23:14of the long-lost lighthouse of Portus.

1:23:16 > 1:23:19I can't see what else it could possibly be.

1:23:19 > 1:23:22Simon, just how exciting is that?

1:23:22 > 1:23:26I mean, it would be pretty hard to overestimate the significance

1:23:26 > 1:23:28of finding this monument.

1:23:28 > 1:23:32I mean, people have been looking for it for hundreds of years.

1:23:32 > 1:23:35The lighthouse of Portus

1:23:35 > 1:23:39was one of the great monuments of the Roman world.

1:23:40 > 1:23:46Commemorated on coins, inscriptions and images all over the Empire.

1:23:46 > 1:23:50It really represents the ultimate symbol of Rome's political

1:23:50 > 1:23:53and military domination of the Mediterranean.

1:23:53 > 1:23:56And indeed, given where the Mediterranean is

1:23:56 > 1:23:59in the Roman Empire, the Empire as a whole.

1:24:03 > 1:24:06'Imagine you're on a ship

1:24:06 > 1:24:10'approaching the great harbour of Rome at night.

1:24:12 > 1:24:15'The sky would have been dark in antiquity...

1:24:18 > 1:24:22'..and the first thing you would have seen is a light,

1:24:22 > 1:24:24'floating in the sky.

1:24:27 > 1:24:29'It's like nothing you've ever seen before.

1:24:34 > 1:24:39'An incomprehensible force, sucking everything in.

1:24:41 > 1:24:43'The people...

1:24:45 > 1:24:46'..the grain...

1:24:48 > 1:24:50'..the slaves...

1:24:53 > 1:24:55'..everything.

1:25:03 > 1:25:08'To visit the probable location of the lighthouse involves a short trek

1:25:08 > 1:25:11'across broken waste ground on the edge of Fiumicino airport.

1:25:13 > 1:25:16'But there is one more surprise in store.'

1:25:17 > 1:25:20OK, now, it's just over here, just there.

1:25:20 > 1:25:22Hang on a second.

1:25:22 > 1:25:24Are you telling me we've come on this entire journey

1:25:24 > 1:25:27to find the ultimate symbol of Rome and it's in a scrap yard?

1:25:27 > 1:25:30Well, let's have a look.

1:25:30 > 1:25:35- Ah, now, Sarah.- Yeah. - The feature that you found...- Right.

1:25:35 > 1:25:38..the platform of what we thought was the lighthouse,

1:25:38 > 1:25:42it was a 140 metres long, 37 metres wide.

1:25:42 > 1:25:45So I calculate that the base of the lighthouse

1:25:45 > 1:25:48would have been 30 metres wide,

1:25:48 > 1:25:50which means that it would have stood

1:25:50 > 1:25:54110 metres high and would have been right over there.

1:26:29 > 1:26:36When we set out to use satellite technology to map the Roman Empire,

1:26:36 > 1:26:41I genuinely thought that it was a completely crazy thing to do!

1:26:46 > 1:26:51What I've come to realise is that my first real love

1:26:51 > 1:26:54has and, I think, always will be finding things.

1:26:58 > 1:27:01Part of me is relieved it's over.

1:27:01 > 1:27:03Just because of all the challenges we've had

1:27:03 > 1:27:05and everything we've been through.

1:27:05 > 1:27:09But part of me kind of wonders what's next.

1:27:14 > 1:27:17It's been a massive privilege watching Sarah work on this trip.

1:27:17 > 1:27:21I'm just so excited that it seems like she's discovered

1:27:21 > 1:27:23the site of Rome's lost lighthouse.

1:27:23 > 1:27:26The symbol of their domination. And I've learnt a lot on this trip

1:27:26 > 1:27:29about what underpinned Rome's domination.

1:27:29 > 1:27:31Yes, Rome was a military power

1:27:31 > 1:27:35but she realised that wars are expensive

1:27:35 > 1:27:39and they create a backlash, they almost inflame opposition.

1:27:39 > 1:27:42So Rome was also a psychological empire.

1:27:42 > 1:27:46Rome overawed people, Rome impressed people,

1:27:46 > 1:27:52Rome won respect by creating prosperity and security.

1:27:52 > 1:27:53So the situation is that

1:27:53 > 1:27:57people actually started wanting to be part of Rome's empire.

1:27:57 > 1:28:00They started collecting their own tax.

1:28:00 > 1:28:02They even started policing themselves.

1:28:02 > 1:28:04Now, that's clever.

1:28:04 > 1:28:08And that's what underpins Rome's greatness.