0:00:33 > 0:00:39It's not often that a ramble in the mountains turns up a great scientific discovery,
0:00:39 > 0:00:43but at Inchnadamph, in the Highlands of Scotland,
0:00:43 > 0:00:46something was found that was so unexpected, so astonishing,
0:00:46 > 0:00:52that it helped explain how the landscape we see today was formed.
0:00:54 > 0:00:57At the end of the 19th century,
0:00:57 > 0:01:02a Mr Peach and a Mr Horne were exploring this area
0:01:02 > 0:01:05when they came upon this cave.
0:01:05 > 0:01:08Inside it,
0:01:08 > 0:01:11they found something almost unbelievable.
0:01:11 > 0:01:16Something that had never been found in Britain before.
0:01:18 > 0:01:23But it wasn't in the mouth of the cave that they made their discovery.
0:01:23 > 0:01:28Oh, no, it was way down in its darkest recesses.
0:01:38 > 0:01:43Imagine exploring this eerie cave by candlelight,
0:01:43 > 0:01:47especially with what was hidden deep underground.
0:01:52 > 0:01:56What did they find when they got here?
0:01:56 > 0:02:00They found the remains of a bear.
0:02:01 > 0:02:04But not just any old bear.
0:02:04 > 0:02:08This is the skull of a polar bear.
0:02:08 > 0:02:10For a polar bear to have lived here,
0:02:10 > 0:02:14it must have been as cold as the Arctic.
0:02:15 > 0:02:19We're not talking millions of years here.
0:02:20 > 0:02:26The skull they found wasn't a fossil, it was real bone.
0:02:26 > 0:02:32Polar bears must have been stalking the Scottish Highlands practically yesterday.
0:02:32 > 0:02:35So, could this have been a scene
0:02:35 > 0:02:40not from the north of Norway or the High Canadian Arctic,
0:02:40 > 0:02:44but from where Blackpool or Bristol are situated today?
0:02:45 > 0:02:51A British Isles where musk ox and polar bears roamed wild?
0:03:00 > 0:03:04The polar bear skull was a tantalising clue
0:03:04 > 0:03:08to a past we might find hard to imagine.
0:03:13 > 0:03:17It was a land locked in permanent winter.
0:03:19 > 0:03:22Britain in the Ice Age.
0:03:31 > 0:03:35These breathtakingly beautiful mountains are not the Himalayas.
0:03:41 > 0:03:44They're not the Alps.
0:03:56 > 0:04:00Neither are they a scene from Lord of the Rings.
0:04:05 > 0:04:07I'm in the Ben Nevis mountain range.
0:04:12 > 0:04:19As high as you can get in the British Isles, and it's like being on top of the world.
0:04:19 > 0:04:22It's winter in the Highlands of Scotland.
0:04:22 > 0:04:27You've never seen anything more spectacular as this. I haven't.
0:04:27 > 0:04:31Over there in the distance, those bobbly bits are the Cairngorms.
0:04:31 > 0:04:34This is the snowiest place in Britain.
0:04:34 > 0:04:38There's snow on the mountain tops even in the middle of summer.
0:04:38 > 0:04:42For all the fact that it's achingly beautiful, it's piercingly cold.
0:04:42 > 0:04:44It's about minus five degrees Celsius,
0:04:44 > 0:04:47but with the wind chill factor, about minus 15.
0:04:47 > 0:04:51Which is why right now, up here in this beauty,
0:04:51 > 0:04:54I'm the only fool here!
0:04:57 > 0:05:02RADIO: Cross-border motorway remains closed around Lockerbie...
0:05:02 > 0:05:06Ben Nevis may have snow all year round,
0:05:06 > 0:05:08but in the rest of the country,
0:05:08 > 0:05:13just one winter storm brings everything to a grinding halt.
0:05:13 > 0:05:15'..across the snowbound area.
0:05:15 > 0:05:19'Four times normal levels. There were 2,000 calls an hour to the AA.
0:05:19 > 0:05:24'Snow making journeys tomorrow equally treacherous.'
0:05:24 > 0:05:29If you're as old as me, you can recall the winter of 1963.
0:05:29 > 0:05:31I was just 13.
0:05:31 > 0:05:36I can remember having to dig through a six-foot snowdrift just to get out of the house.
0:05:37 > 0:05:41It was a winter that dragged on and on,
0:05:41 > 0:05:45with temperatures desperately low,
0:05:45 > 0:05:49and ice and snow from December right through to April.
0:05:54 > 0:05:57But no matter how bad winter gets,
0:05:57 > 0:06:02at least we know that spring is just around the corner.
0:06:04 > 0:06:10From beneath the snowy blanket, new life is poised to emerge.
0:06:12 > 0:06:16Before long, Britain is green and lush once more.
0:06:41 > 0:06:44The seasons change as regular as clockwork.
0:06:44 > 0:06:48But even the best clocks can go wrong.
0:06:53 > 0:06:55Just imagine -
0:06:55 > 0:07:00what if Britain never woke from its long winter sleep?
0:07:00 > 0:07:03Bluebells never burst into life
0:07:03 > 0:07:07and songbirds never sang.
0:07:07 > 0:07:13And imagine if that winter sleep lasted, not for a year but for much, much longer.
0:07:13 > 0:07:19Well, in Britain's past, it did just that.
0:07:19 > 0:07:23We experienced cold, snow and ice like never before.
0:07:23 > 0:07:25Not just a few bad winters,
0:07:25 > 0:07:29but hundreds of thousands of years of deep freeze
0:07:29 > 0:07:32right across northern Europe.
0:07:32 > 0:07:36It was one of the biggest events to influence the shape of our country.
0:07:36 > 0:07:41But it was caused by something on the other side of the Atlantic.
0:07:41 > 0:07:43Three and a half million years ago,
0:07:43 > 0:07:50the then separate continents of North and South America became joined by a land bridge.
0:07:50 > 0:07:54It caused quite a stir.
0:08:12 > 0:08:16The ocean currents in the north Atlantic changed,
0:08:16 > 0:08:20and warm tropical waters flowed towards our land.
0:08:20 > 0:08:25Sounds like a recipe for a balmy Britain, but it wasn't.
0:08:28 > 0:08:34The warm water brought moist air and rain to our western coasts,
0:08:34 > 0:08:38but in the colder north it fell as snow.
0:08:56 > 0:09:01At the same time, the ice sheets in the Arctic expanded,
0:09:01 > 0:09:04and that's when things got worse.
0:09:07 > 0:09:09They acted like a giant mirror.
0:09:09 > 0:09:15The bigger they got, the more the sun's heat was reflected back into space.
0:09:20 > 0:09:23A vicious circle set in
0:09:23 > 0:09:25and temperatures plummeted.
0:09:25 > 0:09:33Our green and varied landscape turned decidedly white and chilly.
0:09:35 > 0:09:40Even the seas at our coast began to freeze.
0:09:46 > 0:09:52At first, once a year, winter briefly loosened its icy grip.
0:09:52 > 0:09:55Animals and plants clung on.
0:09:55 > 0:10:01But gradually the winters became longer and the summers shorter.
0:10:03 > 0:10:05Until eventually, they never came at all.
0:10:05 > 0:10:09The plants and animals of the British Isles
0:10:09 > 0:10:11were about to lose the fight.
0:10:11 > 0:10:19Plants die of cold, the last ones to survive are things like this tiny willow pressed to the ground.
0:10:19 > 0:10:23Mosses, lichens, the odd bit of scrubby grass,
0:10:23 > 0:10:27even these will die away once the snow no longer melts in the summer.
0:10:27 > 0:10:30Then, you've got an ice age.
0:10:37 > 0:10:42For thousands of years, snow fell and never thawed.
0:10:43 > 0:10:47The icy blanket grew thicker and thicker
0:10:47 > 0:10:50and spread further and further south.
0:10:51 > 0:10:55Eventually, Britain was buried in an icy tomb,
0:10:55 > 0:10:58weighing billions and billions of tons.
0:10:58 > 0:11:04Birmingham would have been a mile and a half beneath my feet,
0:11:04 > 0:11:08which gives you some idea of the scale of this freeze up.
0:11:08 > 0:11:11It would have continued northwards to Ben Nevis and beyond,
0:11:11 > 0:11:15out west across Wales and most of Ireland
0:11:15 > 0:11:18and eastwards over East Anglia.
0:11:19 > 0:11:21It was an extraordinary freeze-up
0:11:21 > 0:11:26and all that extra weight had a surprising effect,
0:11:26 > 0:11:29which you can still see today.
0:12:01 > 0:12:05There's nothing quite like an afternoon on the beach, is there?
0:12:05 > 0:12:09Soaking up a few rays, seagulls screeching overhead,
0:12:09 > 0:12:13the sound of the waves lapping gently on the shore,
0:12:13 > 0:12:16the prospect of an ice cream
0:12:16 > 0:12:19and a short walk to the beach for a paddle.
0:12:19 > 0:12:23But on the Scottish Isle of Jura, things aren't quite what they seem.
0:12:29 > 0:12:32I'm most definitely on a pebbly beach,
0:12:32 > 0:12:35but there's something strange about the pebbles.
0:12:36 > 0:12:40These rocks are certainly typical of those that are worn by water,
0:12:40 > 0:12:43because they're all rounded and smooth.
0:12:43 > 0:12:45And yet, they've got lichens growing on them.
0:12:45 > 0:12:49Now lichens only grow on rocks that are stationary.
0:12:49 > 0:12:52Not on those that are washed by water.
0:12:52 > 0:12:54So what's going on?
0:12:54 > 0:12:57While these rocks were clearly once pummelled by the waves,
0:12:57 > 0:13:02they're not any more, because the sea is 40m down there.
0:13:05 > 0:13:09It's hard to believe that this towering cliff
0:13:09 > 0:13:11was once battered by waves.
0:13:11 > 0:13:16This sea stack is now surrounded by grass, not water.
0:13:17 > 0:13:22Waves carved out this arch, but it's been left high and dry.
0:13:24 > 0:13:27And it's all down to ice.
0:13:29 > 0:13:31Like everywhere else on Earth,
0:13:31 > 0:13:36Jura today floats on molten rock about a mile beneath the surface.
0:13:36 > 0:13:40Now when the great ice cap formed, the weight was so great
0:13:40 > 0:13:43it pushed the Earth's surface down into the molten rock.
0:13:43 > 0:13:47And as it melted, so the land rose up again
0:13:47 > 0:13:52and the beach that was once here is now 150 feet up there,
0:13:52 > 0:13:55and still rising.
0:13:55 > 0:14:00So we had enough ice to sink an entire country.
0:14:04 > 0:14:09And Jura's raised beach isn't the only oddity from our icy past.
0:14:09 > 0:14:13Something strange happened further south.
0:14:27 > 0:14:31There were aliens in the Yorkshire Dales.
0:14:36 > 0:14:41These green and rolling hills are typical of limestone country.
0:14:41 > 0:14:45But these giant rocks are certainly not limestone.
0:14:45 > 0:14:47Boulders are strewn everywhere.
0:14:47 > 0:14:54It looks as though they've been tipped off the back of a lorry and allowed to lie where they fell.
0:14:56 > 0:14:58This field is covered in them.
0:14:58 > 0:15:01They look distinctly out of place.
0:15:08 > 0:15:11You can see that when you look at the rocks.
0:15:11 > 0:15:15Down here the native limestone
0:15:15 > 0:15:18and on top of it something completely different -
0:15:18 > 0:15:21darker, lime-green lichens growing all over it,
0:15:21 > 0:15:26and it's perched here like a golf ball on a tee.
0:15:26 > 0:15:30You'd have to be a giant to sink a birdie with a ball this size,
0:15:30 > 0:15:36and people did used to think they were left here by quarrelling giants throwing stones at each other.
0:15:36 > 0:15:39At the time, it was the only explanation,
0:15:39 > 0:15:44because some of these stones come from Northumberland, 100 miles away.
0:15:46 > 0:15:51But giants aren't the only ones strong enough to shift these giant boulders.
0:15:51 > 0:15:55For a less fanciful, but equally impressive explanation
0:15:55 > 0:15:58we need to look again at Britain's icy past.
0:16:02 > 0:16:04This is a glacier -
0:16:04 > 0:16:07it's a river of ice.
0:16:10 > 0:16:13Glaciers are majestic, impressive,
0:16:13 > 0:16:16but fickle and dangerous.
0:16:16 > 0:16:20If I'm going to explain the mystery of Yorkshire's stones,
0:16:20 > 0:16:24I have to venture deep into the glacier's icy heart.
0:16:33 > 0:16:38I've come to Norway and the Jostedalsbreen Glacier.
0:17:15 > 0:17:21It's an eerily silent world of natural ice sculptures and snow,
0:17:21 > 0:17:26but in truth, it's not so quiet, if you know how to listen to it.
0:17:27 > 0:17:29If you take an ice pick
0:17:29 > 0:17:32and make a hole in the ice...
0:17:34 > 0:17:36..you can stick in one of these.
0:17:36 > 0:17:39This is a geologist's microphone.
0:17:39 > 0:17:44If I pack it down in there and then listen to what goes on...
0:17:46 > 0:17:49CRUNCHY CREAKING
0:17:50 > 0:17:52Amazing.
0:17:52 > 0:17:56It's like a tall ship under full sail creaking.
0:18:01 > 0:18:05SLOW, GENTLE CREAKING
0:18:12 > 0:18:16CREAKING CONTINUES
0:18:21 > 0:18:24GHOSTLY CREAKING
0:18:24 > 0:18:28I don't know that I want to be sitting here.
0:18:30 > 0:18:35It may look static, but it's most certainly on the move.
0:18:44 > 0:18:47CREAKING
0:18:49 > 0:18:53And these things are so big, that when they're on the move,
0:18:53 > 0:18:56they're almost impossible to stop.
0:19:13 > 0:19:16The movement is too slow to see,
0:19:16 > 0:19:18but time-lapse cameras
0:19:18 > 0:19:23show that the whole thing is slowly sliding downhill.
0:19:36 > 0:19:40The sheer weight of the glacier helps to keep things moving.
0:19:40 > 0:19:47The pressure on the underside is so great, that the ice melts, and acts as a lubricant.
0:19:47 > 0:19:52It's the same principle that kept Torvill and Dean's skates
0:19:52 > 0:19:54sliding effortlessly on the ice.
0:19:54 > 0:19:59As the glaciers move, they tear up rocks from the ground,
0:19:59 > 0:20:02which then freeze to their base.
0:20:02 > 0:20:07They turn the whole thing into an enormous moving sheet of icy sandpaper.
0:20:15 > 0:20:19When the ice melted, as it did in Yorkshire about 12,000 years ago,
0:20:19 > 0:20:25the glacier's cargo of rocks was dumped miles away from home.
0:20:29 > 0:20:34Because they're so out of place, these rocks are called erratics.
0:20:34 > 0:20:40It's a lovely term for such inconsistent, irregular features in the landscape.
0:20:40 > 0:20:43Once they were scattered all over Britain,
0:20:43 > 0:20:48but over the centuries they've been tidied away by farmers, builders and gardeners.
0:20:48 > 0:20:55But wherever they do still exist, they're a fascinating reminder of our glacial past.
0:20:56 > 0:21:03The icy, glacial sandpaper did more than move a few boulders across the land.
0:21:06 > 0:21:09Glaciers reshaped everything in their path.
0:21:09 > 0:21:14They gouged out some of the British Isles' most spectacular landscapes.
0:21:15 > 0:21:21Here in Killarney, in Southwest Ireland, just as in my native Yorkshire Dales
0:21:21 > 0:21:25or the Lake District, or the uplands of Scotland and Wales,
0:21:25 > 0:21:29the entire landscape was sculpted by ice.
0:21:29 > 0:21:31This is a classic glacial valley -
0:21:31 > 0:21:33broad and steep-sided -
0:21:33 > 0:21:38and you can just imagine the ice bulldozing its way down here.
0:21:38 > 0:21:42The surprising thing is that it only receded 15,000 years ago,
0:21:42 > 0:21:46and in geological terms that's very recent.
0:21:46 > 0:21:51In people terms, it's only 750 generations back!
0:21:54 > 0:22:00It seems amazing that our landscape, which appears so timeless,
0:22:00 > 0:22:02was formed so recently.
0:22:02 > 0:22:09It's the most striking ice age land forms, the spectacular mountains and valleys,
0:22:09 > 0:22:13that we've retained as wilderness on our crowded islands.
0:22:25 > 0:22:31These upland sanctuaries provide a refuge for some of our most treasured wildlife.
0:22:33 > 0:22:39Here animals can still live out their lives, relatively undisturbed.
0:22:40 > 0:22:46The Highlands of Scotland belong to soaring golden eagles...
0:22:52 > 0:22:54..and majestic red deer.
0:23:14 > 0:23:21But they're also a refuge for some of our rarest animals, those that are shy of people...
0:23:22 > 0:23:24..like pine martens...
0:23:32 > 0:23:35..and others, such as red squirrels,
0:23:35 > 0:23:39that are being pushed out by foreign intruders.
0:23:53 > 0:23:56But was all of Britain covered by ice?
0:24:00 > 0:24:04To find out, I'm taking a journey underground.
0:24:24 > 0:24:27If you work in London and you take the tube,
0:24:27 > 0:24:32to pass the time between stations, you'll probably read a novel.
0:24:32 > 0:24:36But the tunnels themselves have a story to tell
0:24:36 > 0:24:38and a secret to reveal.
0:24:38 > 0:24:42When they dug the underground tunnels, all those years ago,
0:24:42 > 0:24:48the soil they took out was all the same kind of clay and gravel, just as you'd expect...
0:24:48 > 0:24:54until they got here, when suddenly it changed...
0:24:54 > 0:24:56at Finchley Road.
0:25:02 > 0:25:08Finchley Road tube station was the end of the line for Britain's enormous wall of ice.
0:25:13 > 0:25:19When the ice melted, it left behind its load of distinctly different rocks and soils
0:25:19 > 0:25:23that showed exactly where the ice stopped.
0:25:23 > 0:25:28You can follow that boundary all the way across Southern England,
0:25:28 > 0:25:33from Bristol, past Oxford to London's Finchley Road.
0:25:33 > 0:25:40If the M4 had existed back then, you could have admired the edge of the ice sheet and its glaciers
0:25:40 > 0:25:42all the way along its length.
0:25:42 > 0:25:48This meant that to the south of the M4, conditions were very different.
0:25:48 > 0:25:50To find out just how different,
0:25:50 > 0:25:55I'll have to look for clues in a rather unexpected place.
0:26:04 > 0:26:07Yes, unlikely as it may seem,
0:26:07 > 0:26:11that "place" is on board a fishing boat.
0:26:11 > 0:26:16Somewhere out here is more evidence of Britain's past.
0:26:24 > 0:26:31This is the North Sea, 80 miles off the British coast, and I'm on a fishing trip with a difference.
0:26:31 > 0:26:35I'm hoping to catch something a bit out of the ordinary.
0:26:56 > 0:26:59What can a net load of starfish and crabs
0:26:59 > 0:27:03tell us about conditions south of the vast ice sheet?
0:27:04 > 0:27:08Well, nothing, but if you're lucky,
0:27:08 > 0:27:11they're not the only things you can catch.
0:27:11 > 0:27:17I'm here with Dick Moll, a specialist not in fish and crabs, but fossils.
0:27:17 > 0:27:23Although, even with his help, finding what we're looking for is harder than expected.
0:27:25 > 0:27:30- That's wood, isn't it? Not a...yeah.- That's a tree.
0:27:30 > 0:27:32A tree. Gardening, you see(!)
0:27:37 > 0:27:39- Wood.- Wood!
0:27:43 > 0:27:45Wood!
0:27:45 > 0:27:47What is that?
0:27:49 > 0:27:51- Wood?- Wood.
0:27:53 > 0:27:56- Is that a bit of rib?- No, wood. - Oh, wood!
0:28:00 > 0:28:03But with the next catch, we struck lucky.
0:28:06 > 0:28:08What does this look like to you?
0:28:10 > 0:28:12A tusk?
0:28:12 > 0:28:16Exactly. This trawler isn't after fish or crabs,
0:28:16 > 0:28:19it's fishing for mammoths.
0:28:19 > 0:28:21It's a good specimen, as well.
0:28:21 > 0:28:26- Excellent!- It weighs a ton! - Heavy?- Very heavy. Ivory?
0:28:26 > 0:28:28This is pure ivory, but fossilised.
0:28:28 > 0:28:32From the bottom of our very own North Sea,
0:28:32 > 0:28:36we'd just pulled up the tusk of a pre-historic mammoth.
0:28:49 > 0:28:54Amazing as this was for me, out here, it's an everyday occurrence.
0:28:55 > 0:28:58And it wasn't just tusks.
0:29:05 > 0:29:09Don't tell me, this is the back leg of a mammoth!
0:29:09 > 0:29:13- Is this the front leg? - It's the front leg...top part.
0:29:13 > 0:29:19- Have we got two pieces of one leg? Maybe?- Maybe one animal.
0:29:19 > 0:29:22These were big animals.
0:29:24 > 0:29:28It'd take some dog to get its jaws around this!
0:29:29 > 0:29:32So far, the remains of 50,000 mammoths
0:29:32 > 0:29:36have been found at the bottom of the North Sea.
0:29:38 > 0:29:42Fishermen first discovered the bones over 100 years ago.
0:29:42 > 0:29:46They gave them to the local doctor for identification.
0:29:46 > 0:29:51And he announced that finally, this was evidence of Noah's flood.
0:29:51 > 0:29:56While opinions on Noah are divided, they were right about the flood.
0:29:58 > 0:30:03During the Ice Age, so much water was locked up in glaciers and ice sheets,
0:30:03 > 0:30:08that sea levels around the world were much lower than today.
0:30:08 > 0:30:11The North Sea didn't exist
0:30:11 > 0:30:16and the Thames was a mere tributary of the ancient German Rhine,
0:30:16 > 0:30:20which ran down the middle of where the English Channel is today.
0:30:23 > 0:30:26All around, was a vast plain,
0:30:26 > 0:30:30a tundra, that stretched between Britain and mainland Europe.
0:30:30 > 0:30:33It looked like Northern Siberia.
0:30:38 > 0:30:43In the winter months, this was a cold and barren place.
0:30:43 > 0:30:47Only animals adapted to sub-zero temperatures could survive.
0:30:49 > 0:30:51Mammoths stood 11ft at the shoulder,
0:30:51 > 0:30:55had six inches of fat under their skin
0:30:55 > 0:30:59and their insulating hair was 3ft long.
0:31:06 > 0:31:09Bison were here too.
0:31:14 > 0:31:20At times, Southern England's deep freeze was well stocked.
0:31:20 > 0:31:26Packs of Arctic wolves would have made the most of it, picking off the young and the weak.
0:31:27 > 0:31:32Come the spring, there was a partial thaw,
0:31:32 > 0:31:35when the land teemed with life.
0:31:37 > 0:31:43In the short summer, the rich pastures attracted huge herds of grazing animals from the south.
0:31:48 > 0:31:55The lower sea level meant that animals could walk to these summer pastures from mainland Europe,
0:31:55 > 0:31:58across what's now the English Channel.
0:32:00 > 0:32:06Imagine a great migration, like those we see today in Alaska and Siberia,
0:32:06 > 0:32:09actually crossing the South Downs.
0:32:09 > 0:32:12Caribou and strange antelope, called saiga,
0:32:12 > 0:32:14travel with the changing seasons.
0:32:16 > 0:32:23The saiga's enlarged nose enables it to breathe more easily in the icy air.
0:32:24 > 0:32:31This is what life could well have looked like on the land that's now below the North Sea.
0:32:33 > 0:32:39Following the herds during the late ice age, was another cold-adapted creature,
0:32:39 > 0:32:44a predator that hunted not with sharp claws and teeth,
0:32:44 > 0:32:46but with a sharp mind.
0:32:46 > 0:32:50The first humans had arrived in Britain.
0:32:50 > 0:32:54One group was well adapted to the cold - the Neanderthals.
0:32:54 > 0:32:58Even though they were around for 200,000 years,
0:32:58 > 0:33:02they didn't leave all that much evidence, but there's enough,
0:33:02 > 0:33:09like Neanderthal bones found at Lynford in Norfolk, to give us a picture of how they lived.
0:33:13 > 0:33:18The popular image of Neanderthals is that they were brutish,
0:33:18 > 0:33:22uncivilised and that they spoke in grunts, but we know that's not true.
0:33:22 > 0:33:27They cared for the sick and elderly, they buried their dead,
0:33:27 > 0:33:32and they had a sophisticated vocabulary. What did they look like?
0:33:36 > 0:33:41These make-up artists transform actors for films and TV.
0:33:41 > 0:33:47They were about to give me a taste of what life might be like as a Neanderthal.
0:33:50 > 0:33:55By studying fossils, we know that although a Neanderthal's skull shape
0:33:55 > 0:33:58was basically the same as ours, there were differences.
0:34:05 > 0:34:10Like chimpanzees and gorillas they had pronounced brow ridges.
0:34:11 > 0:34:17Scientists think these were a leftover from their primate past.
0:34:17 > 0:34:20Modern humans have lost them completely.
0:34:25 > 0:34:27As well as a new forehead,
0:34:27 > 0:34:31I was going to be fitted with a winning smile.
0:34:33 > 0:34:37You'll have to push your top lip out. Push out your lower lip.
0:34:37 > 0:34:44A Neanderthal's teeth would have been worn down from years of chewing tough meat, and cracking bones.
0:34:44 > 0:34:47Theirs were more prominent teeth than ours,
0:34:47 > 0:34:51and the surrounding jaw muscles were stronger and larger.
0:34:51 > 0:34:54The most obvious difference was the nose...
0:34:54 > 0:34:58large and broad,
0:34:58 > 0:35:00for very good reasons.
0:35:00 > 0:35:08It was packed with sinuses that warmed the freezing air, like the enormous nose of the Saiga antelope.
0:35:08 > 0:35:12It made it easier to breathe and be active in the cold.
0:35:15 > 0:35:20I was beginning to feel very odd.
0:35:20 > 0:35:22Who's a pretty boy, then?
0:35:22 > 0:35:26Not even my wife would recognise me now.
0:35:31 > 0:35:34The attention to detail is amazing.
0:35:34 > 0:35:37Skin colour, skin pores, wrinkles.
0:35:37 > 0:35:42Everything is finely sculpted and painted by hand.
0:35:53 > 0:35:58Neanderthals probably didn't shave so would have had facial hair.
0:35:58 > 0:36:01But there's no evidence they were hairier than us.
0:36:08 > 0:36:12And they probably didn't worry too much about hairstyle.
0:36:12 > 0:36:16I can't believe anyone would know it was me.
0:36:16 > 0:36:19I don't think I do.
0:36:19 > 0:36:22Transformation complete.
0:36:25 > 0:36:29In just four hours I've turned into a caveman.
0:36:29 > 0:36:35Some scientists think Neanderthals were so closely related to us,
0:36:35 > 0:36:39that if one walked down the street today, no-one would notice.
0:36:39 > 0:36:41Now there's a challenge I can't refuse.
0:36:49 > 0:36:55For someone who is used to being recognised in the street, it was quite nice to be lost in the crowd.
0:36:57 > 0:37:00Most people didn't give me a second look.
0:37:00 > 0:37:04Although occasionally I got a sideways glance...
0:37:04 > 0:37:07just briefly.
0:37:09 > 0:37:12Neanderthals may have lived in caves.
0:37:12 > 0:37:16They may have survived the worst conditions Britain has ever seen.
0:37:16 > 0:37:21They may have disappeared 30,000 years ago.
0:37:21 > 0:37:24But what this little experiment shows is that, really,
0:37:24 > 0:37:29Neanderthals may not have been that different from us,
0:37:29 > 0:37:30after all.
0:37:36 > 0:37:41But they were certainly better suited to a life in Ice Age Britain.
0:37:41 > 0:37:45Their short, stocky bodies helped conserve heat, and powerful muscles
0:37:45 > 0:37:48turned them into endurance athletes.
0:37:48 > 0:37:51And they needed to be fit.
0:37:51 > 0:37:54Neanderthals were real meat lovers.
0:37:54 > 0:37:58Analysing their bones shows that it made up most of their diet.
0:37:58 > 0:38:02The problem was finding it.
0:38:02 > 0:38:05Southern Britain didn't have much in the way of plants,
0:38:05 > 0:38:08and although the land bridge was handy for cross-channel visits,
0:38:08 > 0:38:12not many animals could be found there in the winter months.
0:38:16 > 0:38:21Hunting parties would travel for miles in the hope of finding real bounty
0:38:24 > 0:38:31And a mammoth, by anyone's standards, is more than a mouthful.
0:38:32 > 0:38:36But how could such small people tackle such huge creatures?
0:38:36 > 0:38:40Well, they were bright, these Neanderthals.
0:38:47 > 0:38:52They turned the natural landscape into a death trap.
0:38:56 > 0:39:01They drove their prey over the edge of cliffs.
0:39:24 > 0:39:29And this is one of those cliff-side traps discovered on Jersey,
0:39:29 > 0:39:32in the Channel Islands, at La Cotte de St Brelade.
0:39:35 > 0:39:39Mammoths met their deaths at the base of these cliffs.
0:39:43 > 0:39:47Their bones - an evidence of Neanderthal butchery -
0:39:47 > 0:39:49have been found right here.
0:39:54 > 0:39:57They may have been cavemen, but they were cunning.
0:40:00 > 0:40:04But all this talk of mammoths and Neanderthals,
0:40:04 > 0:40:08glaciers and ice sheets, is telling only half the story.
0:40:08 > 0:40:14For most of the last two million years the Ice Age was certainly cold,
0:40:14 > 0:40:17but there's a final twist to this tale in London.
0:40:18 > 0:40:22When Trafalgar Square - this great monument to Nelson -
0:40:22 > 0:40:24was being built in the 1830s,
0:40:24 > 0:40:29the builders dug up an extraordinary collection of exotic bones.
0:40:29 > 0:40:33And these bones had a history and a story to tell.
0:40:33 > 0:40:36Take this, for example.
0:40:36 > 0:40:44It's 120,000 years old, and that places it slap bang in the middle of the Ice Age.
0:40:44 > 0:40:47But it's not from a woolly mammoth or a polar bear.
0:40:47 > 0:40:51It's from an animal you'd least expect to find in the cold.
0:40:51 > 0:40:54This is the tooth of a hippopotamus.
0:41:00 > 0:41:05They also found the bones of other animals that would now be more at home in Africa -
0:41:05 > 0:41:10hyenas, lions, rhinoceros, and even the tooth of an elephant -
0:41:10 > 0:41:14straight-tusked, mind you.
0:41:14 > 0:41:19So what are these animals doing in Britain in the middle of the Ice Age?
0:41:19 > 0:41:23Well, we now know that the Ice Age was not unrelentingly cold.
0:41:23 > 0:41:28It was punctuated by warmer periods, some of them much warmer even than today.
0:41:28 > 0:41:36And these bones prove that 120,000 years ago, right here in the centre of London,
0:41:36 > 0:41:40the icy wilderness was replaced by Serengeti Plains.
0:41:46 > 0:41:52It's hard to believe there could have been such dramatic swings in the climate and the wildlife.
0:42:00 > 0:42:03Glaciers to swamps.
0:42:03 > 0:42:06Mammoths to hippos.
0:42:06 > 0:42:13But there's no doubt that's what happened here, and over much of the rest of the country too.
0:42:13 > 0:42:15On safari...
0:42:15 > 0:42:16in the Ice Age?
0:42:20 > 0:42:23Well, the term "Ice Age" is a bit misleading actually.
0:42:23 > 0:42:27"Dramatic Change Age" would be more accurate.
0:42:27 > 0:42:32Wherever you live, the locality would have been gripped in ice for several thousand years,
0:42:32 > 0:42:37then a warmer period would have come, then more ice and then another warmer period and so on.
0:42:37 > 0:42:39In fact scientists reckon
0:42:39 > 0:42:47there could have been as many as 30 separate ice ages over the last two million years.
0:42:47 > 0:42:49Why have there been so many climate swings?
0:42:49 > 0:42:55Because the Earth doesn't orbit the sun in a perfect and unvarying circle.
0:42:55 > 0:43:01While it's orbiting it also tilts on its axis very slowly over thousands of years,
0:43:01 > 0:43:05and as it tilts closer to the sun it gets warmer,
0:43:05 > 0:43:13and as it tilts away from the sun, it gets cooler - cool enough to cause an Ice Age.
0:43:13 > 0:43:21Around 15,000 years ago the northern hemisphere started to tilt towards the sun once again.
0:43:21 > 0:43:27The great ice sheets began to melt and Britain was eventually released from its icy tomb.
0:44:08 > 0:44:13As the ice disappeared so did the tundra, and the animals that lived on it.
0:44:16 > 0:44:20And from beneath the ice, a very different landscape was about to emerge.
0:44:55 > 0:44:58Mountains, lochs, hills and valleys...
0:44:58 > 0:45:04when the ice retreated, most, if not all, of our countryside had been affected in some way,
0:45:04 > 0:45:10either by the ice itself or by the torrents of water that flowed from the melting glaciers.
0:45:13 > 0:45:16Everything had been altered irrevocably.
0:45:24 > 0:45:27So, has the Ice Age left us completely?
0:45:27 > 0:45:29Not quite.
0:45:29 > 0:45:30In the remotest glens,
0:45:30 > 0:45:32on the highest peaks,
0:45:32 > 0:45:34it lingers even now -
0:45:34 > 0:45:38in places like Rannoch Moor, where I started this journey.
0:45:38 > 0:45:45If Britain is ever gripped by another ice age, this is where it will start.
0:45:45 > 0:45:50And up here, as if waiting for that time to come again,
0:45:50 > 0:45:55some refugees from the last big freeze can still be found.
0:45:58 > 0:46:02The ptarmigan lives on the highest mountains in Scotland.
0:46:02 > 0:46:08It's white winter plumage - a reminder of its Arctic roots.
0:46:09 > 0:46:14This place is also home to Arctic hares.
0:46:14 > 0:46:18Their shorter ears and longer hair help to keen them warm.
0:46:25 > 0:46:31As the ice retreated these animals took refuge in our chilly uplands.
0:46:37 > 0:46:42The last isolated pockets of Ice Age Britain.
0:46:58 > 0:47:05The landscape we see today is almost entirely the result of that most recent ice age.
0:47:05 > 0:47:07There's no reason to assume it'll be the last.
0:47:07 > 0:47:12This is probably just a warm period before the next big freeze.
0:47:12 > 0:47:17But the most dramatic effect of the last one was that when the ice melted,
0:47:17 > 0:47:20the level of the world's seas rose.
0:47:20 > 0:47:25Our land was cut off from mainland Europe.
0:47:25 > 0:47:28The British Isles were born.