0:00:05 > 0:00:10Our planet is full of incredible natural wonders.
0:00:10 > 0:00:11Look at that!
0:00:13 > 0:00:15Whoo!
0:00:15 > 0:00:17It has immense power...
0:00:20 > 0:00:25..and yet, that's rarely mentioned in our history books.
0:00:26 > 0:00:29I'm here to change that.
0:00:32 > 0:00:36I'm looking at four ways the power of the planet
0:00:36 > 0:00:38has shaped our history.
0:00:46 > 0:00:50The power of fire...
0:00:50 > 0:00:52Oh...
0:00:52 > 0:00:55..that fuelled great technological breakthroughs.
0:00:56 > 0:00:57Wind...
0:00:57 > 0:00:59HE CHUCKLES
0:01:01 > 0:01:04..that has influenced the rise and fall of empires.
0:01:07 > 0:01:09Water...
0:01:11 > 0:01:17Our struggle to control it has directed human progress.
0:01:19 > 0:01:24But I'm going to start by looking inside the Earth itself.
0:01:26 > 0:01:30It's an unknown world, hot and extreme.
0:01:32 > 0:01:35HE CHUCKLES
0:01:37 > 0:01:42It's provided the raw materials for our conquest of the planet,
0:01:42 > 0:01:43but at a price.
0:01:47 > 0:01:53This is the great untold story of human history.
0:02:07 > 0:02:10Hidden unseen within the Earth,
0:02:10 > 0:02:12extraordinary geological forces are at work.
0:02:12 > 0:02:16Hi. Gracias.
0:02:16 > 0:02:18Forces that have shaped our history.
0:02:21 > 0:02:24To really understand and appreciate them,
0:02:24 > 0:02:26I've got to go deep into the Earth itself.
0:02:32 > 0:02:36This is the Naica mine in northern Mexico -
0:02:36 > 0:02:39the starting point for a journey to one of the most
0:02:39 > 0:02:45spectacular and extreme places on or in the planet.
0:02:45 > 0:02:48I'm really starting to feel it now.
0:02:48 > 0:02:53I'm getting hotter and hotter, the deeper in I go.
0:02:53 > 0:02:56This heat is just a taste of what lies ahead.
0:03:02 > 0:03:06Finally, I arrive at what they call "Base Camp".
0:03:06 > 0:03:12You know, where I'm heading is just so extreme, so oppressive
0:03:12 > 0:03:18that I'm going to need all of these people, all of these control systems
0:03:18 > 0:03:22and all of this kit over here just to get there.
0:03:22 > 0:03:24It's going to be like visiting another planet.
0:03:27 > 0:03:31Beyond here is a chamber that reveals the power of the inner Earth
0:03:31 > 0:03:33to influence human affairs.
0:03:33 > 0:03:35But to get there,
0:03:35 > 0:03:38they've had to develop some pretty esoteric equipment.
0:03:40 > 0:03:42Get this.
0:03:42 > 0:03:45It's like a chain mail of ice cubes.
0:03:45 > 0:03:47It's heavy, isn't it?
0:03:47 > 0:03:50The special refrigerated suit will keep me cool.
0:03:50 > 0:03:51What a palaver!
0:03:53 > 0:03:56- This brings down my core temperature? - Yes.
0:03:56 > 0:03:58Oh, feels very cold suddenly.
0:03:58 > 0:04:01That's very odd!
0:04:02 > 0:04:05But it's not the heat alone that's potentially lethal.
0:04:08 > 0:04:11This is what? This is the oxygen?
0:04:11 > 0:04:15Yes, it's fresh air.
0:04:15 > 0:04:17- It's fresh air. - Yes. You'll need it.
0:04:17 > 0:04:21The heat is combined with nearly 100% humidity.
0:04:21 > 0:04:23If I breathed that combination,
0:04:23 > 0:04:26moisture would begin to condense inside my lungs.
0:04:26 > 0:04:30After about ten minutes, I'd start to suffocate.
0:04:30 > 0:04:33- You're ready. - I'm ready? I don't feel ready.
0:04:33 > 0:04:36OK.
0:04:40 > 0:04:42Without this suit, I could die.
0:04:42 > 0:04:44It seems a lot of effort,
0:04:44 > 0:04:49but inside there is one of the geological wonders of the world.
0:04:55 > 0:04:57HE BREATHES HEAVILY
0:05:09 > 0:05:12WONDROUS MUSIC
0:05:27 > 0:05:30That is unbelievable.
0:05:39 > 0:05:41This is just mad!
0:05:43 > 0:05:45Absolutely gorgeous, isn't it?
0:05:48 > 0:05:51This is la Cueva de los Cristales -
0:05:51 > 0:05:54for my money, the most spectacular cave of crystals
0:05:54 > 0:05:56discovered anywhere in the world.
0:05:58 > 0:06:00HE CHUCKLES
0:06:00 > 0:06:03You know, I've travelled around the world
0:06:03 > 0:06:06to see some of the most amazing geology,
0:06:06 > 0:06:09but this place - this place just tops it all.
0:06:09 > 0:06:12Look at it.
0:06:14 > 0:06:16It really looks perfect.
0:06:18 > 0:06:21You can see through them, they're so translucent.
0:06:21 > 0:06:23And there's different types.
0:06:23 > 0:06:25You can see these ones that are like roses building up
0:06:25 > 0:06:31and then these columns, these pillars - absolutely magnificent.
0:06:40 > 0:06:45Until recently, no-one knew this chamber existed.
0:06:45 > 0:06:49It was uncovered when miners broke through by chance.
0:06:58 > 0:07:01You know, these extraordinary crystals
0:07:01 > 0:07:05are made up almost entirely of a pretty ordinary mineral - gypsum -
0:07:05 > 0:07:10but it's the sheer scale of them that astounds you.
0:07:17 > 0:07:20This strange world is shaped by forces
0:07:20 > 0:07:24that have had a profound impact on human civilisation.
0:07:31 > 0:07:34HE PANTS
0:07:37 > 0:07:40Oh, this heat... This heat's just too much.
0:07:40 > 0:07:42It's unbearable.
0:07:42 > 0:07:45But, oh, hey, the heat - that's what it's all about.
0:07:45 > 0:07:47That's the whole point.
0:07:47 > 0:07:51It's this cauldron that's the reason that these crystals are here.
0:07:55 > 0:08:00It's so hot because only about 5km below the cavern...
0:08:01 > 0:08:07..is an area of the Earth's crust that is super-heated molten rock.
0:08:12 > 0:08:17This heats water, which dissolves minerals from the surrounding rock.
0:08:17 > 0:08:22Phenomenal pressure forces this mineral-rich water
0:08:22 > 0:08:26up through cracks in the rock and filled this giant cavern.
0:08:28 > 0:08:30Here, the conditions were perfect
0:08:30 > 0:08:33for the minerals to slowly crystallise back out of the water.
0:08:33 > 0:08:38The cave lay undisturbed for over half a million years,
0:08:38 > 0:08:43so the gypsum crystals just kept growing
0:08:43 > 0:08:47until the miners broke through and the cave was drained.
0:08:50 > 0:08:55But the hot inner Earth has done far more than create these crystals.
0:08:56 > 0:09:01This incredible hot world hidden just beneath the surface
0:09:01 > 0:09:04is a driving force for powerful geological events
0:09:04 > 0:09:08that have shaped the fate of peoples throughout history.
0:09:15 > 0:09:20This is the Timna Valley in Israel's Negev Desert.
0:09:21 > 0:09:24Today it's pretty well deserted.
0:09:24 > 0:09:28But over 6,000 years ago,
0:09:28 > 0:09:29this place witnessed
0:09:29 > 0:09:32one of the world's first great scientific breakthroughs.
0:09:40 > 0:09:41Up until this point,
0:09:41 > 0:09:45humans had made all their tools from stuff just lying around -
0:09:45 > 0:09:48stone, wood, bone,
0:09:48 > 0:09:50anything, really, that they could get their hands on.
0:09:52 > 0:09:55But then, between 6,000-7,000 years ago,
0:09:55 > 0:10:00our ancestors made an extraordinary imaginative leap.
0:10:00 > 0:10:05They realised that the rock here contained a secret.
0:10:07 > 0:10:11These green bands are called malachite.
0:10:11 > 0:10:13And it was these malachite seams
0:10:13 > 0:10:15that around 6,500 years ago
0:10:15 > 0:10:19were at the centre of that incredible leap of human ingenuity.
0:10:22 > 0:10:26Like the gypsum inside the crystal cave,
0:10:26 > 0:10:28these bands of malachite
0:10:28 > 0:10:32formed when hot fluids rose from deep inside the planet
0:10:32 > 0:10:34and leaked into these rocks.
0:10:39 > 0:10:40But unlike gypsum,
0:10:40 > 0:10:43when malachite is heated up...
0:10:48 > 0:10:50..it does something special.
0:10:51 > 0:10:56It releases a metal.
0:10:56 > 0:10:58Copper.
0:11:14 > 0:11:15You know, in its day,
0:11:15 > 0:11:19this copper axe head would have been the pinnacle of technology.
0:11:19 > 0:11:21For a start, it's weighty.
0:11:21 > 0:11:25If you hit something or someone with this, it would leave a dent.
0:11:25 > 0:11:29For another thing, it's hard enough to take an edge.
0:11:29 > 0:11:32And if it gets blunt, you just sharpen it up.
0:11:34 > 0:11:39You can still see evidence of the ancient smelting pits at Timna.
0:11:42 > 0:11:47But the copperworkers left behind a more striking memorial to their work.
0:11:53 > 0:11:58A network of hundreds of tunnels, all carved by hand.
0:12:01 > 0:12:06This was the first large-scale mining anywhere on the planet.
0:12:07 > 0:12:09Those early copper miners
0:12:09 > 0:12:14would have squeezed through these narrow shafts on all fours,
0:12:14 > 0:12:17smashing their way through the rock
0:12:17 > 0:12:22and hauling their pails of copper-laced ore back to the surface.
0:12:32 > 0:12:33You know, the copper revolution
0:12:33 > 0:12:35changed our relationship with the planet
0:12:35 > 0:12:37in a really profound way.
0:12:37 > 0:12:39For the first time,
0:12:39 > 0:12:41we were transforming what the Earth offered us
0:12:41 > 0:12:45and in the process creating entirely new resources.
0:12:45 > 0:12:48And copper was just the start of things to come.
0:12:54 > 0:12:58About 5,000 years ago, tin was added to copper
0:12:58 > 0:13:03to form a new, more durable metal alloy - bronze.
0:13:09 > 0:13:13By 3,000 years ago, refinements to the smelting process
0:13:13 > 0:13:17meant iron could be smelted out of rock.
0:13:20 > 0:13:25Metal tools became the foundation for human civilisation.
0:13:31 > 0:13:36So it's clear we owe a huge debt to those first copper miners at Timna.
0:13:39 > 0:13:42But we also owe a debt to the deep Earth.
0:13:45 > 0:13:50The key to Timna's role in early history is its location.
0:13:57 > 0:14:02The Earth's crust is divided into huge pieces called plates.
0:14:02 > 0:14:05Where they meet are cracks known as fault lines.
0:14:08 > 0:14:11Timna is next to the Dead Sea fault,
0:14:11 > 0:14:13which separates Africa from Arabia.
0:14:15 > 0:14:20This fault also connects Timna to the deep, hot interior of the Earth.
0:14:23 > 0:14:25It's this hot interior
0:14:25 > 0:14:27that is ultimately the source
0:14:27 > 0:14:30of all the metals that have so radically changed our history.
0:14:33 > 0:14:36Fault lines allow them to rise to the surface...
0:14:42 > 0:14:46..just as they did at the crystal cave in Mexico.
0:14:55 > 0:14:58But fault lines began affecting human history
0:14:58 > 0:15:01even before the discovery of metals.
0:15:01 > 0:15:06In fact, we've been strangely drawn to these boundary zones
0:15:06 > 0:15:08ever since the dawn of civilisation.
0:15:11 > 0:15:12And you can see why
0:15:12 > 0:15:16in the barren wilderness of the Lut Desert in Iran.
0:15:18 > 0:15:24The landscape is covered in hundreds of holes arranged in rows.
0:15:24 > 0:15:26These holes in the desert
0:15:26 > 0:15:30can help explain our ancient attraction to fault lines.
0:15:33 > 0:15:38But that involves me going down one -
0:15:38 > 0:15:41something the locals seem a little bemused by.
0:15:43 > 0:15:44Hi.
0:15:45 > 0:15:47So this is it?
0:15:47 > 0:15:49HE SPEAKS LOCAL LANGUAGE
0:15:51 > 0:15:53That's tiny!
0:15:53 > 0:15:56I don't think I'll really fit.
0:15:56 > 0:15:59How deep is it?
0:16:02 > 0:16:04ROCK THUDS
0:16:06 > 0:16:10God! Apparently it's 50 metres.
0:16:10 > 0:16:13That's over 150 feet.
0:16:13 > 0:16:15OK, I guess we do it, huh?
0:16:15 > 0:16:18So we go down?
0:16:20 > 0:16:23And if this deep, dark hole wasn't scary enough,
0:16:23 > 0:16:28the method for going down is unconventional at best.
0:16:28 > 0:16:30So we take this, like a pulley?
0:16:32 > 0:16:34And this goes over the top, I guess.
0:16:35 > 0:16:37So do I go on this?
0:16:39 > 0:16:42You can't buy those, I bet you!
0:16:42 > 0:16:46I've never gone on a rope with a tripod pulled by a tractor before.
0:16:46 > 0:16:47So...
0:16:48 > 0:16:51TRACTOR ENGINE REVS
0:16:54 > 0:16:57Well, I think we should just do this before I change my mind.
0:16:57 > 0:16:59OK. What could possibly go wrong now?
0:17:04 > 0:17:08Blooming heck. It really is deep.
0:17:24 > 0:17:27Oh, this isn't natural.
0:17:27 > 0:17:30I'm getting lowered down into the bowels of the Earth here.
0:17:33 > 0:17:36I wasn't sure if I was claustrophobic
0:17:36 > 0:17:39but now I realise I think I am.
0:17:40 > 0:17:42It's so far up!
0:17:43 > 0:17:45Look at that.
0:17:45 > 0:17:47Oh, dear. I don't want to do this too many times.
0:17:50 > 0:17:51HE EXHALES
0:17:51 > 0:17:54METAL TAPS
0:17:55 > 0:17:57For over 2,000 years,
0:17:57 > 0:18:01local people have been digging shafts like this - by hand.
0:18:01 > 0:18:05And I get the sense I'm about to find out why.
0:18:05 > 0:18:07HE SIGHS
0:18:07 > 0:18:09All right, here we go.
0:18:09 > 0:18:10Hey hey!
0:18:10 > 0:18:13Ooh! Oof!
0:18:13 > 0:18:14WATER SPLASHES
0:18:14 > 0:18:16I misjudged it.
0:18:16 > 0:18:19Look at this!
0:18:19 > 0:18:21This is the answer.
0:18:21 > 0:18:25The essential ingredient of every civilisation on Earth.
0:18:26 > 0:18:28Cold, fresh drinking water.
0:18:28 > 0:18:32This is what made this remote corner of the Lut Desert
0:18:32 > 0:18:36one of the few places in the region that could sustain towns and cities.
0:18:36 > 0:18:38And I'll tell you...
0:18:38 > 0:18:42..after a trip like that, this is so nice to have.
0:18:42 > 0:18:44HE SIGHS
0:18:44 > 0:18:48Right. I'm off to explore a bit.
0:18:50 > 0:18:54I want to find where the water's coming from.
0:18:59 > 0:19:04This tunnel leading off the shaft is called a qanat.
0:19:06 > 0:19:09It's one of many in this region,
0:19:09 > 0:19:11hacked out of solid rock
0:19:11 > 0:19:15to capture ground water that's stored deep below the desert.
0:19:16 > 0:19:20I feel as if I'm in an underground rain shower.
0:19:28 > 0:19:32I've travelled about, I don't know, a couple of hundred metres now
0:19:32 > 0:19:34and it seems to be getting smaller and smaller.
0:19:35 > 0:19:37HE GROANS
0:19:37 > 0:19:39It's a bit narrow here.
0:19:43 > 0:19:44Well, this is it.
0:19:44 > 0:19:47This is the source of all this water.
0:19:47 > 0:19:49It's just pouring in from here.
0:19:52 > 0:19:55Underground water exists beneath most deserts.
0:19:55 > 0:19:57But it's usually so far down,
0:19:57 > 0:20:00there's no practical way of getting at it.
0:20:00 > 0:20:03The difference is, here there's a fault line.
0:20:07 > 0:20:09The fault is full of thick clay
0:20:09 > 0:20:12produced by the grinding of the surrounding rocks
0:20:12 > 0:20:14as they rub along the fault line.
0:20:14 > 0:20:19This forms a clay dam, which water can't penetrate.
0:20:19 > 0:20:23Water flowing down from the mountains
0:20:23 > 0:20:24pools against the dam,
0:20:24 > 0:20:27creating an underground reservoir
0:20:27 > 0:20:32through which a qanat is dug to channel the water.
0:20:32 > 0:20:35Gravity does the rest.
0:20:37 > 0:20:42So originally the water would've been banked up against this fault line,
0:20:42 > 0:20:45unable to penetrate through the clay-rich barrier.
0:20:45 > 0:20:49But what the locals did was to cut a qanat across the fault line,
0:20:49 > 0:20:52breaching the barrier and releasing the water.
0:20:52 > 0:20:55It was a simple but brilliant piece of engineering.
0:20:56 > 0:20:57OK.
0:21:08 > 0:21:14Qanats were an ingenious early example of a mains water supply.
0:21:14 > 0:21:17The shaft is simply a way
0:21:17 > 0:21:19to get access to the tunnel carrying the water, so it can be repaired.
0:21:21 > 0:21:25Today, the qanats still carry water from underneath the Lut Desert
0:21:25 > 0:21:27into the nearby city of Bam,
0:21:27 > 0:21:33as well as irrigating date orchards for which this area is famous.
0:21:46 > 0:21:49Oh! Oh, it's so good to see blue sky.
0:21:49 > 0:21:50Oh!
0:21:50 > 0:21:52Yeah, thank you.
0:21:52 > 0:21:55But this place isn't a one-off.
0:21:55 > 0:21:59In fact, if you look back at the ancient world,
0:21:59 > 0:22:02you see a strong link between fault lines,
0:22:02 > 0:22:08water and the growth of some of the first cities.
0:22:10 > 0:22:14More than 2,000 years ago, Petra in Jordan
0:22:14 > 0:22:17was the most important trade hub in the Middle East.
0:22:23 > 0:22:27It was built along a branch of the Dead Sea fault
0:22:27 > 0:22:32and was entirely dependent on natural springs,
0:22:32 > 0:22:36which rose along the fault and fed its irrigation system.
0:22:46 > 0:22:51Nearby is Jericho, said to be the oldest city in the world.
0:22:51 > 0:22:55It was first settled 10,000 years ago
0:22:55 > 0:22:58because deep ground water rose along fault lines
0:22:58 > 0:23:02to create fertile pastures in the desert.
0:23:07 > 0:23:11More unusual is the ancient Roman city of Hierapolis.
0:23:11 > 0:23:15It was built next to these terraces of white rock.
0:23:23 > 0:23:25Here, it wasn't just water that was important -
0:23:25 > 0:23:31minerals carried in the water were thought to have revitalising powers.
0:23:32 > 0:23:36So Hierapolis became an important healing centre
0:23:36 > 0:23:38in the Roman Empire.
0:23:47 > 0:23:51Whether it was minerals, metals or water,
0:23:51 > 0:23:55ancient civilisations were repeatedly drawn to the resources
0:23:55 > 0:23:58that fault lines brought up from the deep Earth.
0:24:02 > 0:24:07It's a connection which led 11 of the 13 most important civilisations
0:24:07 > 0:24:09of the ancient world
0:24:09 > 0:24:13unknowingly to build their cities close to a plate boundary.
0:24:19 > 0:24:22As the earliest civilisations developed,
0:24:22 > 0:24:25so the relationship between fault lines and human history
0:24:25 > 0:24:27became more sophisticated.
0:24:27 > 0:24:29They even played a role
0:24:29 > 0:24:33in the establishment of the most advanced early civilisation of all.
0:24:36 > 0:24:384,000 years ago, in the Bronze Age,
0:24:38 > 0:24:41the island of Crete was home to the Minoans.
0:24:56 > 0:24:59Their showpiece was the palace of Knossos.
0:25:08 > 0:25:11You can see by the sheer scale and sophistication of Knossos
0:25:11 > 0:25:15that the Minoans weren't just another early civilisation.
0:25:15 > 0:25:19This, in a way, was the beginning of modern society.
0:25:19 > 0:25:20Certainly, this was a place
0:25:20 > 0:25:23that you and I would have felt reasonably at home.
0:25:30 > 0:25:33There was running water, a sewage system
0:25:33 > 0:25:36and large stores of food and wine.
0:25:43 > 0:25:48It all allowed the Minoans to create a new kind of society.
0:25:52 > 0:25:55For me, all this is a moment in history
0:25:55 > 0:25:58that is much under appreciated.
0:25:58 > 0:26:01What the Minoans represent is a great pivotal point
0:26:01 > 0:26:05when life switched from being dictated
0:26:05 > 0:26:07by the grim realities of survival
0:26:07 > 0:26:09into something that we could actually enjoy.
0:26:09 > 0:26:14What the Minoans invented was the day off.
0:26:16 > 0:26:21And the Minoans took their pioneering responsibilities
0:26:21 > 0:26:23in this area very seriously.
0:26:24 > 0:26:26Now, this may look like a car park,
0:26:26 > 0:26:29but, really, this is where the paraphernalia
0:26:29 > 0:26:32of the Minoan leisure society really took off
0:26:32 > 0:26:36because this is one of world's first sports stadiums.
0:26:44 > 0:26:47In its day, 500 spectators would cram in here
0:26:47 > 0:26:49to watch boxing, wrestling,
0:26:49 > 0:26:53and the Minoans' most peculiar sport, bull-leaping.
0:26:53 > 0:26:57The basic idea was that you wait for a massive bull to run at you,
0:26:57 > 0:26:58then at the crucial moment,
0:26:58 > 0:27:02you grab hold of the horns and flip yourself over the top.
0:27:04 > 0:27:06How do you practise that?
0:27:11 > 0:27:14No-one knows why the Minoans leapt over bulls,
0:27:14 > 0:27:18but this bizarre sport was a forerunner to bull-fighting.
0:27:24 > 0:27:28But the real legacy of the Minoans was how they made their wealth.
0:27:32 > 0:27:34This was the Bronze Age.
0:27:36 > 0:27:40To make bronze, you need two metals - copper and tin.
0:27:43 > 0:27:46The problem was finding them.
0:27:52 > 0:27:57For the Minoans, copper was relatively near at hand in Cyprus,
0:27:57 > 0:27:59thanks to the fault line beneath it.
0:28:06 > 0:28:08Tin was trickier.
0:28:08 > 0:28:11Inside the Earth's crust, only two parts per million are tin,
0:28:11 > 0:28:14so it's much rarer.
0:28:17 > 0:28:20The hunts for tin led to distant lands
0:28:20 > 0:28:23that were at the edge of the then-known world.
0:28:29 > 0:28:32One such place was so full of tin
0:28:32 > 0:28:36that it was called the Cassiterides - "the tin islands".
0:28:36 > 0:28:38Today...
0:28:40 > 0:28:41..we know it as Britain.
0:28:48 > 0:28:51But the centres of Bronze-Age civilisation
0:28:51 > 0:28:55were in the Mediterranean, 3,000km away.
0:28:55 > 0:28:59Tin was also found in other far-flung locations
0:28:59 > 0:29:03like Spain, Central Europe and even Iran...
0:29:04 > 0:29:07..which meant tin had to be traded,
0:29:07 > 0:29:10and for this, Crete was perfectly positioned.
0:29:15 > 0:29:17The Minoans exploited their position
0:29:17 > 0:29:21at the crossroads of many different trading routes...
0:29:23 > 0:29:28..to become the world's first maritime superpower.
0:29:30 > 0:29:32It may not seem like it today,
0:29:32 > 0:29:37but in Bronze Age times, this island was at the centre of the known world,
0:29:37 > 0:29:38with the mineral-rich heartlands
0:29:38 > 0:29:42of Europe, the Middle East and North Africa all around.
0:29:42 > 0:29:46For the Minoans, it wasn't so much about owning the raw materials
0:29:46 > 0:29:50as knowing what to do with them, how to put them together.
0:29:50 > 0:29:54They built an empire because they'd worked out how to exploit the geology
0:29:54 > 0:29:56that their neighbours had on their doorsteps.
0:30:03 > 0:30:05By the time of the Minoans,
0:30:05 > 0:30:07fault lines had been a crucial factor
0:30:07 > 0:30:11in the success of many early civilisations.
0:30:17 > 0:30:20But the Earth extracted a price for these riches.
0:30:22 > 0:30:27It was a price paid in full by the Minoans.
0:30:28 > 0:30:32At the heart of the story was a small archipelago
0:30:32 > 0:30:34100km north of Crete.
0:30:38 > 0:30:41Today that island chain is known as Santorini,
0:30:41 > 0:30:46famous for its pretty white houses and rugged coastline.
0:30:56 > 0:31:00But at the time of the Minoans this was a busy port,
0:31:00 > 0:31:03the key to their trading empire.
0:31:05 > 0:31:07If Crete was the heart of the Minoan culture,
0:31:07 > 0:31:10then this place was its backbone,
0:31:10 > 0:31:14a centre of industry that helped fuel what was at the time
0:31:14 > 0:31:17the most advanced civilisation on the planet.
0:31:20 > 0:31:23But Santorini held a deadly secret.
0:31:26 > 0:31:27Unknown to the Minoans,
0:31:27 > 0:31:31it sat above one of the Earth's major plate boundaries.
0:31:35 > 0:31:38Santorini formed when the African plate
0:31:38 > 0:31:41started sliding below the European plate.
0:31:43 > 0:31:47As the African plate melted inside the deep Earth,
0:31:47 > 0:31:50molten rock rose back to the surface
0:31:50 > 0:31:52to create what is actually a volcano.
0:31:54 > 0:31:57OMINOUS RUMBLING
0:31:57 > 0:32:00Around 3,500 years ago,
0:32:00 > 0:32:04this volcano did what volcanoes tend to do -
0:32:04 > 0:32:05it blew up.
0:32:15 > 0:32:17Unluckily for the Minoans,
0:32:17 > 0:32:21it was the biggest eruption of the last 10,000 years.
0:32:23 > 0:32:27Today you can still trace why the eruption was so devastating
0:32:27 > 0:32:29in the cliffs around Santorini.
0:32:34 > 0:32:40This cliff is made entirely of ash and rock spat out by the volcano.
0:32:40 > 0:32:43It's got distinct layers to it,
0:32:43 > 0:32:46each of which are from different stages of the eruption.
0:32:46 > 0:32:50In other words, this rock face is a timeline of events.
0:32:53 > 0:32:56Climbing this cliff helps understand the disaster
0:32:56 > 0:33:01that was unlike anything anyone had ever seen before.
0:33:08 > 0:33:10This level here was the start of the eruption.
0:33:10 > 0:33:14I'm kind of standing on the Minoan land surface.
0:33:14 > 0:33:15And in the next five hours,
0:33:15 > 0:33:19the eruptions threw out an enormous mushroom cloud of debris.
0:33:24 > 0:33:26It just rained down ash after ash after ash.
0:33:32 > 0:33:35This stuff is just like a silica glass.
0:33:35 > 0:33:38It gets into your lungs and it just lacerates your lungs.
0:33:38 > 0:33:39You just choke on it.
0:33:55 > 0:33:57This innocent-looking gravel
0:33:57 > 0:34:01was from the second and most lethal stage of the eruption.
0:34:04 > 0:34:06Sea water invaded the volcano
0:34:06 > 0:34:09and that mix of water with molten lava
0:34:09 > 0:34:11produced a series of incredibly violent eruptions
0:34:11 > 0:34:15that punched a jet of superheated gas and debris
0:34:15 > 0:34:16high into the atmosphere.
0:34:24 > 0:34:27As these clouds of hot gas and lava fell back to Earth,
0:34:27 > 0:34:31they engulfed the outer edges of the island.
0:34:31 > 0:34:33Ay!
0:34:36 > 0:34:41But, incredibly, the worst was still to come.
0:34:44 > 0:34:47Once the volcano had spewed out everything that was in its guts,
0:34:47 > 0:34:50the weight of it collapsed into the void below,
0:34:50 > 0:34:53producing the most enormous blast.
0:34:53 > 0:34:56And in the death throes of that final blast,
0:34:56 > 0:34:59there was one last catastrophic flourish.
0:35:05 > 0:35:09The centre of the volcano crashed into the sea.
0:35:16 > 0:35:20That sudden collapse created a gigantic tsunami...
0:35:22 > 0:35:27..which quickly spread out across the Aegean towards Crete.
0:35:30 > 0:35:33WAVE CRASHES
0:35:34 > 0:35:38For a civilisation whose strength was in their navy,
0:35:38 > 0:35:41the tsunami would have been devastating.
0:35:46 > 0:35:50It's thought that as the tsunami swept through the Aegean,
0:35:50 > 0:35:52it engulfed the Minoan harbours,
0:35:52 > 0:35:57and any boats in them would have been smashed into matchsticks.
0:35:57 > 0:35:59So perhaps it's not that surprising that not a single boat
0:35:59 > 0:36:01from the vast Minoan fleet
0:36:01 > 0:36:03has ever been found.
0:36:11 > 0:36:16This was a catastrophe from which the Minoans would never recover.
0:36:25 > 0:36:29A long chalk-and-ash cloud and a giant tsunami
0:36:29 > 0:36:33meant that this maritime power was on its knees.
0:36:33 > 0:36:36With the fleet gone,
0:36:36 > 0:36:40and their most strategic trading post obliterated,
0:36:40 > 0:36:43the Minoans went downhill fast.
0:36:43 > 0:36:45Within a century or so of the eruption,
0:36:45 > 0:36:50this once-great civilisation was finished.
0:36:55 > 0:36:56The eruption of Santorini
0:36:56 > 0:36:59was an extreme event.
0:36:59 > 0:37:01But ancient history is littered with
0:37:01 > 0:37:05tales of cities destroyed along plate boundaries.
0:37:11 > 0:37:15And it's not just volcanoes that do the damage.
0:37:15 > 0:37:19Fault lines are also home to another deadly force of nature.
0:37:28 > 0:37:30Earthquakes.
0:37:30 > 0:37:35Recent events in Haiti are a reminder of just how devastating earthquakes can be.
0:37:35 > 0:37:42The appalling disaster is a terrible example of how the destructive power of the deep Earth
0:37:42 > 0:37:46can be concentrated along fault lines.
0:37:47 > 0:37:49Over the past 10,000 years,
0:37:49 > 0:37:55many cities first established to take advantage of fault lines
0:37:55 > 0:37:58have been flattened.
0:38:00 > 0:38:04Hierapolis, with its famous health spa,
0:38:04 > 0:38:08was destroyed by a giant earthquake in AD 60.
0:38:12 > 0:38:16Jericho, the oldest city in the world,
0:38:16 > 0:38:20has been hit over 15 times by large earthquakes.
0:38:20 > 0:38:21Some believe it was this
0:38:21 > 0:38:25that famously brought its walls "tumbling down".
0:38:28 > 0:38:31Likewise, Petra was abandoned
0:38:31 > 0:38:36after an earthquake demolished its irrigation system in AD 360.
0:38:41 > 0:38:44And it continues to this day.
0:38:44 > 0:38:48In 2003, the city of Bam, famous for its qanats,
0:38:48 > 0:38:50was devastated by a massive earthquake
0:38:50 > 0:38:53which killed over 30,000 people.
0:39:06 > 0:39:10It makes you realise that, in effect, much of human history
0:39:10 > 0:39:14has centred on a bargain between us and the inner Earth.
0:39:15 > 0:39:18Plate boundaries provide access
0:39:18 > 0:39:21to resources from deep inside the planet.
0:39:25 > 0:39:31But live near one, and you also live with the risk of a sudden catastrophic disaster.
0:39:35 > 0:39:38But even the most advanced of our ancestors
0:39:38 > 0:39:41had no way of explaining this strange coincidence.
0:39:42 > 0:39:45In fact, it's only in the last 50 years
0:39:45 > 0:39:48that scientists have finally understood
0:39:48 > 0:39:53the bargain that was inadvertently struck all those years ago.
0:39:53 > 0:39:57You can see the theory in action in the middle of the Pacific Ocean.
0:40:00 > 0:40:04This is Kilauea on Hawaii's Big Island.
0:40:08 > 0:40:11It's one of the most active volcanoes on the planet
0:40:11 > 0:40:15because it's fed by a chamber of magma deep inside the Earth
0:40:15 > 0:40:17called a hot spot.
0:40:27 > 0:40:32The hot spot has effectively punched a hole in the Pacific plate -
0:40:32 > 0:40:35the piece of the Earth's crust on which Hawaii sits.
0:40:36 > 0:40:41But remove the ocean around Hawaii and something strange is revealed -
0:40:41 > 0:40:44a chain of mountains stretching along the sea bed
0:40:44 > 0:40:48for over 5,000km.
0:40:48 > 0:40:51This line of extinct volcanoes is explained
0:40:51 > 0:40:56when you realise that the Pacific plate is continually on the move.
0:41:00 > 0:41:03As the plate drifts over this stationary hot spot,
0:41:03 > 0:41:06a volcano forms,
0:41:06 > 0:41:08but after about a million years,
0:41:08 > 0:41:11the moving plate pulls the volcano away from the hot spot.
0:41:12 > 0:41:17Meanwhile, another eruption begins, forming a new island.
0:41:23 > 0:41:29Today, Kilauea is still growing, but it hasn't got long to go.
0:41:29 > 0:41:33In a few thousand years, it will drift away from the hot spot
0:41:33 > 0:41:36and eventually disappear beneath the waves.
0:41:47 > 0:41:51The Hawaiian islands chain is a beautiful demonstration
0:41:51 > 0:41:54of a big idea
0:41:54 > 0:41:56that explains why plate boundaries
0:41:56 > 0:42:02bring us extraordinary benefits and terrible hazards in equal measure.
0:42:03 > 0:42:07It's called plate tectonics.
0:42:10 > 0:42:14The key is that all the plates, which divide the Earth's surface
0:42:14 > 0:42:15are continually on the move.
0:42:17 > 0:42:20Where they collide, they crumple the land
0:42:20 > 0:42:23to form great mountain ranges, like the Himalayas.
0:42:27 > 0:42:30Where they pull apart,
0:42:30 > 0:42:33oceans form in the gap.
0:42:37 > 0:42:39The friction of this continual movement
0:42:39 > 0:42:42means that plate boundaries become melting zones
0:42:42 > 0:42:44where minerals are concentrated
0:42:44 > 0:42:47and are able to rise towards the surface.
0:42:50 > 0:42:54But the flip side is that huge amounts of energy
0:42:54 > 0:42:57are concentrated along the plate boundaries.
0:43:00 > 0:43:05When one plate slides underneath another, volcanoes form.
0:43:16 > 0:43:20When two plates lock together and then suddenly break free,
0:43:20 > 0:43:23the jolt causes devastating earthquakes.
0:43:30 > 0:43:34So we now know that plate boundaries are so rich in resources
0:43:34 > 0:43:38for exactly the reasons they're so dangerous.
0:43:41 > 0:43:45Yet the strange thing is this groundbreaking discovery
0:43:45 > 0:43:48has made little difference to where we live.
0:43:53 > 0:43:56If you look at the plate boundaries,
0:43:56 > 0:43:59it's clear that many cities are located close by.
0:44:01 > 0:44:05In fact, 10 of the 20 largest cities in the world
0:44:05 > 0:44:08are next to dangerous fault lines.
0:44:09 > 0:44:12So why are we still building next to these danger zones?
0:44:15 > 0:44:18In the rugged hills of central California
0:44:18 > 0:44:20is part of the answer.
0:44:25 > 0:44:28And to see it, I'm heading into the skies.
0:44:28 > 0:44:30At least, I hope I am.
0:44:30 > 0:44:33This is the dinkiest helicopter I've ever been in.
0:44:35 > 0:44:37It'll be nice when it's finished.
0:44:41 > 0:44:43MOTOR STARTS
0:45:09 > 0:45:11I'm going to see
0:45:11 > 0:45:15perhaps the most famous geological feature on the planet.
0:45:15 > 0:45:17And this is the best way to find it.
0:45:21 > 0:45:26Yeah, yeah, yeah, this is it. This looks fantastic.
0:45:30 > 0:45:34It's this beautiful funnel cut right through these hills here.
0:45:34 > 0:45:36That's amazing.
0:45:43 > 0:45:46This line of hills with a trench cut through the middle
0:45:46 > 0:45:49is the San Andreas Fault.
0:45:51 > 0:45:55This fault is a boundary between the North American Plate to the east
0:45:55 > 0:45:57and the Pacific Plate to the west.
0:45:59 > 0:46:03For 25 million years, they've been grinding past each other
0:46:03 > 0:46:06to create the largest earthquake fault in North America.
0:46:09 > 0:46:13The San Andreas Fault starts up there in northern California,
0:46:13 > 0:46:17then slices down through 700 miles through here
0:46:17 > 0:46:19down to the border with Mexico.
0:46:19 > 0:46:22As it goes, it cuts through cities and towns
0:46:22 > 0:46:26and passes across a path of roads, bridges,
0:46:26 > 0:46:28aqueducts and fibre-optic cables.
0:46:33 > 0:46:35If ever there was a fault line
0:46:35 > 0:46:38that cut through the very fabric of a modern society,
0:46:38 > 0:46:40then it's this one.
0:46:42 > 0:46:46But a good reason why over 20 million people
0:46:46 > 0:46:49carry on living so close to this danger zone
0:46:49 > 0:46:53is that this plate boundary has made California rich.
0:46:57 > 0:47:00It began with the Californian gold rush.
0:47:02 > 0:47:06These nuggets of gold might have been found in streams,
0:47:06 > 0:47:10but the gold originally rose in hot mineral-rich fluids
0:47:10 > 0:47:12forced up between the plates.
0:47:18 > 0:47:23In fact, almost everything that makes California wealthy
0:47:23 > 0:47:27is at least partly related to the San Andreas Fault.
0:47:28 > 0:47:31Take, for example, the scenery.
0:47:31 > 0:47:33It was the colliding plates
0:47:33 > 0:47:36that forced up mountains along the Californian coast.
0:47:40 > 0:47:45And this dramatic landscape attracts thousands of tourists every year,
0:47:45 > 0:47:50who spend an estimated 2 billion on sightseeing alone.
0:47:51 > 0:47:53Then there's the wine.
0:47:53 > 0:47:55That's partly down to the San Andreas too.
0:47:57 > 0:47:59California is mostly desert
0:47:59 > 0:48:03but when moist air rolls in off the ocean and hits the mountains,
0:48:03 > 0:48:08it rises to form rain that irrigates this otherwise arid landscape.
0:48:12 > 0:48:14It's a microclimate that has made this
0:48:14 > 0:48:17one of the most productive farming regions in America.
0:48:21 > 0:48:25But the ultimate gift of the San Andreas is this.
0:48:28 > 0:48:30HISSING
0:48:35 > 0:48:37Oil.
0:48:38 > 0:48:39Black gold.
0:48:39 > 0:48:42This is an oil seep,
0:48:42 > 0:48:45which is when oil leaks to the surface, like a natural spring.
0:48:47 > 0:48:49HISSING
0:48:49 > 0:48:53Except this is black and gooey.
0:48:53 > 0:48:55Look at that.
0:48:55 > 0:48:58150 years ago, when the first people were looking for oil,
0:48:58 > 0:49:01even the most witless prospector
0:49:01 > 0:49:05realised that places like this were a good place to drill.
0:49:07 > 0:49:11And drill they did.
0:49:12 > 0:49:18Over the years, around 200,000 wells have been sunk here.
0:49:25 > 0:49:29Most people probably think of Texas as America's oil state
0:49:29 > 0:49:35but California was and still is one of the world's biggest oil producers,
0:49:35 > 0:49:38drawing more than 700,000 barrels of crude oil
0:49:38 > 0:49:41out of the ground every day.
0:49:48 > 0:49:51The oil formed millions of years ago, deep inside the Earth.
0:49:51 > 0:49:55But it was the San Andreas Fault which split the rock
0:49:55 > 0:49:59and brought it close enough to the surface to be exploited.
0:50:04 > 0:50:06So it seems that the San Andreas Fault
0:50:06 > 0:50:09has brought California some serious economic benefits.
0:50:09 > 0:50:13Its shaping of the land has created the conditions for oil,
0:50:13 > 0:50:17for agriculture, for wine and even for tourism.
0:50:17 > 0:50:19But how much is that really worth?
0:50:24 > 0:50:28The money men have done the sums.
0:50:28 > 0:50:33They reckon this state earns around 100 billion every year
0:50:33 > 0:50:35because of the San Andreas Fault.
0:50:38 > 0:50:43California's geology is a licence to print money.
0:50:45 > 0:50:47Earthquake geologists like me
0:50:47 > 0:50:51know that California gets struck by a big seismic shake
0:50:51 > 0:50:53every 100 to 150 years.
0:50:53 > 0:50:56And those major quakes are hugely destructive.
0:50:56 > 0:50:59That doesn't seem to dampen the spirits
0:50:59 > 0:51:02of the number-crunchers that are in these skyscrapers.
0:51:02 > 0:51:05It's worked out that in a city like LA,
0:51:05 > 0:51:10a major earthquake will cause up to 250 billion worth of damage.
0:51:10 > 0:51:12Now, that is a huge sum.
0:51:12 > 0:51:16But averaged out over a century, you're still in profit.
0:51:16 > 0:51:19You've got 100 billion a year coming in,
0:51:19 > 0:51:22versus a one-off hit of 250 billion.
0:51:22 > 0:51:25That's a gain of 40 to 1.
0:51:25 > 0:51:29Any economist will tell you that's a pretty decent return.
0:51:32 > 0:51:3310,000 years
0:51:33 > 0:51:37after our ancestors first settled along plate boundaries,
0:51:37 > 0:51:41the benefits of living along a fault line are as potent as ever.
0:51:48 > 0:51:51The point is that in pure economic terms,
0:51:51 > 0:51:56we're still financially better off living along a fault line than not,
0:51:56 > 0:51:58even when it's one of the most active in the world.
0:51:58 > 0:52:01But the problem that I have with that equation
0:52:01 > 0:52:05is that life's not just about money.
0:52:13 > 0:52:21Istanbul, the only city in the world to straddle Asia and Europe.
0:52:21 > 0:52:24This location at the crossroads of two continents
0:52:24 > 0:52:28has made it a trading hub for centuries.
0:52:30 > 0:52:32That's why I find it so exciting.
0:52:32 > 0:52:35It's a vibrant, bustling, cosmopolitan place.
0:52:40 > 0:52:46But Istanbul's location also brings with it great danger.
0:52:52 > 0:52:55Nearby lies the North Anatolian Fault,
0:52:55 > 0:52:59one of the most seismically active plate boundaries on the planet.
0:52:59 > 0:53:05Scientists reckon a major earthquake is due here any time.
0:53:09 > 0:53:12There's little doubt that in the very near future,
0:53:12 > 0:53:15Istanbul will be struck by a big earthquake.
0:53:15 > 0:53:17It's a strange feeling
0:53:17 > 0:53:22that this city that I love could be destroyed in my lifetime.
0:53:24 > 0:53:26But it doesn't have to be.
0:53:29 > 0:53:33Here, they're starting to rewrite the terms
0:53:33 > 0:53:36of our ancient bargain with fault lines.
0:53:36 > 0:53:40The aim is to enjoy the benefits of living along this plate boundary
0:53:40 > 0:53:43without having to pay a price in human life.
0:53:46 > 0:53:49Below the waters of the Bosphorus,
0:53:49 > 0:53:51the channel that separates Europe from Asia,
0:53:51 > 0:53:53is a clue to the solution.
0:54:09 > 0:54:12You know, this is such an eerie feeling.
0:54:12 > 0:54:14I'm 35m below the level of the Bosphorus
0:54:14 > 0:54:16and I'm walking parallel
0:54:16 > 0:54:19to one of the most active earthquake zones in the world.
0:54:19 > 0:54:23So not the kind of place you expect to find a major engineering project,
0:54:23 > 0:54:24and yet that's exactly where
0:54:24 > 0:54:29the Turkish authorities decided to build an underground train line.
0:54:31 > 0:54:35This tunnel, which will one day link Asia to Europe,
0:54:35 > 0:54:37is the deepest tunnel of its kind on Earth
0:54:37 > 0:54:39and yet it runs alongside
0:54:39 > 0:54:43one of the most dangerous earthquake faults in the world.
0:54:48 > 0:54:52These engineers are confident they've got the risks covered.
0:54:52 > 0:54:54Through some technical wizardry,
0:54:54 > 0:54:56the whole tunnel's designed to absorb the vibrations
0:54:56 > 0:54:58of even the largest of earthquakes.
0:54:58 > 0:55:01What these guys are doing, effectively,
0:55:01 > 0:55:03is confronting the earthquake threat head-on.
0:55:06 > 0:55:09This technology won't allow us to stop earthquakes,
0:55:09 > 0:55:11but it shows
0:55:11 > 0:55:15that if we really want to protect against their consequences, we can.
0:55:15 > 0:55:22Unfortunately, in Istanbul, this tunnel is only half the story.
0:55:24 > 0:55:27You know, high-tech underground train tunnels are all very well,
0:55:27 > 0:55:31but the reality is that most people who'll die in the next earthquake
0:55:31 > 0:55:35will die because the buildings that they live and work in collapse.
0:55:35 > 0:55:39And in that sense, Istanbul is completely unprepared.
0:55:39 > 0:55:42It's reckoned that when the next earthquake comes,
0:55:42 > 0:55:45it might bring down a quarter of the city.
0:55:45 > 0:55:47And the thing is, it doesn't have to be like that,
0:55:47 > 0:55:52because we have the technical know-how to keep buildings standing.
0:55:53 > 0:55:57The irony is Istanbul already has a building
0:55:57 > 0:56:00that has survived earthquakes for centuries.
0:56:09 > 0:56:13This magnificent building is the Hagia Sophia.
0:56:13 > 0:56:15It's got to be my favourite place in the city.
0:56:15 > 0:56:18For the tourists that come here,
0:56:18 > 0:56:21this is a fitting symbol of Istanbul's reputation
0:56:21 > 0:56:24as a crossroads of different civilisations.
0:56:24 > 0:56:28In its 1,500-year history, it's been a church and a mosque
0:56:28 > 0:56:30and now a museum.
0:56:32 > 0:56:37The Hagia Sophia has stood through more than a dozen earthquakes,
0:56:37 > 0:56:39without the benefit of modern technology.
0:56:39 > 0:56:43It was built on such a massive, monumental scale
0:56:43 > 0:56:48that even the biggest earthquakes never managed to knock it down.
0:56:58 > 0:57:01You know, it's no accident that when the earthquake does strike,
0:57:01 > 0:57:04the two things that'll probably survive
0:57:04 > 0:57:08are one of the oldest buildings in the city and one of the newest.
0:57:08 > 0:57:11And that's because they're both structures
0:57:11 > 0:57:14that we've decided are worthy of looking after.
0:57:17 > 0:57:21Today, we have the technology to protect every building -
0:57:21 > 0:57:25whether it's flats, factories or offices...
0:57:26 > 0:57:28..if we choose to.
0:57:33 > 0:57:36For 10,000 years,
0:57:36 > 0:57:39we've lived with the benefits and the dangers of fault lines.
0:57:47 > 0:57:50You know, it's clear that people
0:57:50 > 0:57:53are going to continue to live along fault lines -
0:57:53 > 0:57:55probably for the next 10,000 years.
0:57:55 > 0:57:58But now we have two clear options -
0:57:58 > 0:58:01stick with the old regime and take our chances
0:58:01 > 0:58:06or embrace the new and take some kind of control.
0:58:06 > 0:58:10The trouble is, protection doesn't come cheap.
0:58:10 > 0:58:16Reinforcing every building in an earthquake zone would be massively expensive.
0:58:16 > 0:58:19So even with all our knowledge,
0:58:19 > 0:58:23the deep Earth is going to continue to confront us with some tough choices
0:58:23 > 0:58:26for years to come.
0:58:29 > 0:58:33Next time - the magic of water.
0:58:33 > 0:58:36It's constantly transforming itself,
0:58:36 > 0:58:39shifting between guises and from place to place.
0:58:39 > 0:58:46Our struggle to control it has shaped the destiny of some of the greatest civilisations in history.
0:58:59 > 0:59:02Subtitles by Red Bee Media Ltd
0:59:02 > 0:59:05E-mail subtitling@bbc.co.uk