Original subtitles

Europe 3 billion years ago...

born of violence and upheaval...

scoured by wind-blasted deserts...

swallowed by the oceans...

and cloaked in tropical swamps...

these sweeping changes laid the foundations

for the most diverse of continents.

But then, some two and a half million years ago,

this virgin world faced a fresh assault.

Triggered by the most unusual combination

of cosmic and global events,

europe was now confronted by a radical change in climate.

The landscape was transformed beyond recognition...

...locked in a tomb of ice.

These were the ice ages, a raw and challenging time.

This onslaught of climatic change had a profound impact on the land.

How did this new era of extremes shape the europe we know today?

The alps - the very heart of europe.

Millions of visitors come here every year

to enjoy the exhilaration of winter...

...a glimpse of a time when much

of europe was gripped in the big freeze.

Remnants of the ice ages are found right across the continent,

but this is the most spectacular...

...the matterhorn- an iconic pyramid of rock

jutting almost 4,500 metres into the sky.

Travel back through time, over a period of

just twenty thousand years,

and the landscape was very different indeed.

An island in a sea of ice.

Only its tip would have been visible.

Back then, conditions in the

alps and in northern europe were extremely harsh.

Relentless icy storms swept the land.

Temperatures plunged to well below minus 50 degrees celsius.

What triggered this climatic onslaught?

As the earth goes about its orbit,

its pathway periodically shifts taking it closer to...

or further away from... the sun.

As well as this - in a rhythm of its own-

the earth's axis tilts.

About two and a half million years ago

these factors combined to cause cooling in europe's higher latitudes.

Summers became shorter...

...and winters more severe.

But cold alone does not constitute an ice age.

This chill was dramatically intensified by a range of other events...

one of which happened thousands

of kilometres away on the far side of the atlantic.

As north and south america began to join,

they blocked the flow of water from the atlantic to the pacific,

diverting a warm, tropical current back towards europe:

The gulf stream was born.

And with it came masses of moisture-laden air.

When these clouds reached the colder atmosphere of northern europe,

they delivered enormous quantities of snow.

As temperatures plummeted, survival became increasingly hard.

A whole new cast of cold-adapted animals moved in...

rather like today's musk oxen... with their shaggy,

windproof coats and stocky frames.

In the ever-shortening summers,

animals like reindeer too would have eked out

a living on lichens and mosses.

But as temperatures dropped below minus 40 degrees

celsius even these hardy creatures would have

been forced south to warmer climes.

Year after year, snow built upon snow,

compacting into solid ice, engulfing the continent.

Even the sea began to freeze.

The expanse of ice acted like a giant mirror,

reflecting the sun's warmth back into space.

Colossal ice sheets up to two thousand metres

thick spread across the continent covering siberia,

scandinavia and scotland.

We now know how far south the ice sheet reached,

thanks to evidence found in some surprising places.

During the construction of the london underground

in the late 19th century,

scientists unearthed unusual sediment patterns

in the very centre of london.

They revealed that the edge of the northern ice sheet was more

or less here - at the finchley road tube station.

Just imagine how london might have looked about half

a million years ago when the ice ages were at their most extreme.

Other glacial deposits indicate that the edge

of the ice spanned the european continent...

...touching on amsterdam...

...and also berlin...

a freeze-up of this scale will change the whole shape of a continent.

This is the north sea, off the coast of holland.

Although this may seem a normal fishing trip,

these dutch trawler men aren't after sole or plaice.

They're actually scientists on an unusual mission,

in search of a far more intriguing catch.

Among the piles of starfish, crabs and driftwood

they find the long-submerged remains of a far larger animal.

When bones like these were first hauled out more than a century ago,

they were presented to a local doctor for identification.

He declared them to be clear evidence of noah's flood.

Whatever your belief about noah,

the doctor was right about the flood

because these are the bones of land animals...

massive ones at that... woolly mammoths.

What are they doing in the middle of the north sea?

During the ice ages the sea level was around 100 metres lower than today.

Back then the north sea was all dry land...

its water locked up in the ice sheets

to the north and in mountain glaciers.

These mammoth bones tell us something else, too:

Not all of europe was buried in ice.

The north sea was one vast green valley- a tundra.

Standing 3 metres tall and wrapped in dense fur,

woolly mammoths were well adapted to life on these cold,

grassy plains, which they shared

with relatives of today's saiga antelopes.

Their over-sized noses help to warm the chilly air as they inhale,

and to preserve precious moisture as they breathe out.

Saigas came to eurasia from

north america across the bering straits,

an important land bridge when sea levels were lower.

And with them came przewalski's horses-

the ancestors of our modern horse.

As the climate kept changing,

the edge of the ice sheets shifted, and so did entire eco-systems.

But the most surprising ice age immigrants came from the south.

Here in london during the 1830's,

builders constructing nelson's column in

trafalgar square made some extraordinary discoveries.

They unearthed the bones of some very un-ice age

and indeed un-european animals:

Hippos, rhinos, hyenas, and even lions.

Around 120,000 years ago,

western europe must have looked more like east africa.

Over the past 2? Million years,

the climate has sea-sawed from subtropical to arctic and back again.

These warm "interglacial periods"...

lasting as long as 100,000 years...

have allowed plenty of time for new waves

of life to establish themselves on the continent...

before being driven back again by the next cold spell.

This thermal pulsing was rapid and extreme,

with at least 20 different climatic cycles.

Right now we're enjoying one of the warmer periods in between.

It's a sobering thought that this extreme climatic

change has not been an exception, but the rule.

The last major glacial period began 115,000 years ago.

It was to have an immense impact in shaping the continent we know today.

Back then, much of the land would have been inhospitable.

Natural shelters were highly prized.

One ice age creature totally depended on these caves: The cave bear.

In an ice age winter, deep caves were vital for hibernating bears.

But their peace- and indeed their future-

was about to be shattered by others who also sought refuge here.

Neanderthals - ice age specialists like the cave bear.

They braved the continent's harshest climate ever.

For over 150,000 years,

neanderthals remained europe's top predators.

But now a new force was on the move...

a force destined to have a profound impact on the continent.

Modern humans - our ancestors.

Some 40,000 years ago homo sapiens began to advance

into asia and europe from their homelands in africa...

living a nomadic existence... following the migratory herds.

For these inventive and adaptable hunters, this new land,

in spite of its harsh climate, offered a wealth of big game.

Although neanderthals and modern humans certainly crossed paths,

in this vast continent encounters between them must have been rare.

Yet for neanderthals, time was running out.

Their populations were shrinking.

About 30,000 years ago they vanished from the face of the land,

possibly decimated by disease or conflict

or an inability to deal with climate change.

15,000 years ago the shape of the earth's orbit-

and the tilting of its axis-

would come to spell the end of the last great ice age.

In the northern hemisphere summers now became longer...

and winters less severe.

As temperatures rose rapidly in northern europe-

by as much as 10 degrees celsius in less than a century-

the melt gathered momentum.

Massive volumes of water,

a hundred thousand years worth of snowfall,

cascaded off the ice sheets.

This great melt swelled vast river networks.

Old rivers found new courses where the ice had once been.

Violent torrents carried a massive cargo of debris,

filling low-lying valleys with rubble, thus creating europe's plains.

Rivers like the elbe and volga would have been many times

their current size and power.

From the smaller ice caps of the

alps and pyrenees to the great northern ice sheets,

rivers flowed in spate.

Much of this melt water was trapped before it reached the sea.

Tens of thousands of new lakes were created.

The most impressive of them all - 18,000 square kilometres-

is lake ladoga on the finnish-russian border,

europe's largest body of freshwater.

Free from the weight of the scandinavian ice cap,

the land began to rise, cutting lake ladoga off from the sea.

Today, it is a remote natural refuge-

one of the wild fringes of europe.

Lake ladoga is also home to a rare animal

which became trapped here about 9000 years ago

when the lake was finally isolated from the sea.

Ladoga ringed seals.

Today, just a couple of thousand of them remain.

They once inhabited the open sea but have adapted

to life in this freshwater lake.

Ice age relics like these are found

in cold enclaves across the continent.

As the climate warmed up, they retreated to

europe's highest latitudes and highest altitudes...

wherever the arctic climate lingers on.

From the alps to the highlands of

scotland - mountain ranges across europe are arctic islands.

Ibex are ice age immigrants from the mountain ranges of central asia.

Ibex would have followed the edge of the

ice sheets to the west and remained here after the ice retreated.

During the cold periods, some of these

ice age immigrants were spread across most of the continent.

Now remnant populations are thousands of kilometres apart.

The ptarmigan, a bird of the arctic tundra,

now inhabits the alps, northern scandinavia and scotland.

Their winter plumage-

perfect camouflage and insulation - is an echo of the icy past.

Ptarmigans share these mountaintops with another ice age character,

the mountain hare.

It has shorter ears than brown hares, helping reduce heat loss,

and its broad feet make perfect snow shoes.

Snow buntings nest both in the high

arctic and 3000 km south in the high alps.

But it's not only ice age animals that remind us of our frozen past.

Europe still bears the scars of the mightiest,

most dynamic ice age force of all-

a force that created much of the landscape

we're familiar with today: Glaciers.

This is how europe may have looked tens of thousands of years ago.

Glaciers may appear rigid and sedentary,

but they're quite the opposite,

particularly those on steep mountain slopes.

By condensing time they come to life.

Glaciers slip and slide at

a surprising rate- up to 20 metres a week.

Like a river of ice.

The glacier's enormous weight makes

the ice masses glide on a film of water.

As it glides, it rips rocks and boulders from the

ground and pulls them along.

Like giant sandpaper, the glacier smooths its

rocky bed.

The impact of glaciers on the landscape is all too clear...

from the wide, u-shaped valleys of scotland...

...to the deep fjords of norway.

And from spain's picos de europa.

...to the gorges of the alps.

But glaciers do more than carve out valleys.

Like super-sized conveyor belts,

they carry massive loads of rocky debris,

sometimes hundreds of kilometres from their source.

This rocky load piles up where the glacier ends

or is left behind when it melts...

forming distinctive piles of rubble known as "moraines".

Some of the best evidence of this can be found here at segonzano,

in the dolomites of italy.

Lurking in the forest is a group of bizarre collection of pillars.

Legend has it that once these were trolls,

punished for their carelessness.

They're actually the remains of moraine,

dumped here by an ice age glacier.

Over thousands of years, rain has washed away

the soft clays and gravels except

where it was protected by a hard stone cap.

Strangely enough, even some seemingly desert landscapes

owe their whole existence to the last ice age.

Where has all this sand come from?

When the baltic ice sheet melted an enormous heap

of rubble was dropped into the sea...

eroded into sand...

and then washed ashore along the northern flanks of poland,

like here at slowinski national park.

The process continues today...

the glacial dunes are expanding by 9 metres a year...

and swallowing everything in their path.

During the last ice age, mineral-rich glacial dust,

known as "loess", was blown from the alpine ice cap

as far as the black sea.

Millions of tonnes of it were spread across

eastern europe along the danube valley laying

the foundations for what has now become a rich agricultural landscape.

These super-fertile plains are the largest on the continent-

almost 50,000 square kilometres

of cropland yielding wheat, rye, barley and oats.

The breadbasket of europe.

All this productive land we're so familiar with today,

only exists because the peaks

of the alps were ground to dust by glaciers

and carried here by the ice age winds.

After the great melt, when the ice sheets covering most

of northern europe had disappeared,

they left behind a barren, rocky moonscape.

But as temperatures rose, pioneering plants and lichens,

which can cling to bare rock, began to re-colonize the land.

Gradually, in sheltered spots,

more complex plants took hold... their seeds carried on the wind.

In time the soils were restored...

...and the re-greening of europe had begun.

Soon the continent lay swathed in grassland, peat bog and tundra.

For a while, animals like reindeer were in their element,

exploiting these verdant pastures.

But as temperatures continued to rise,

the reindeer retreated north.

The tundra on which they depended would soon be forest.

Conifer trees, like larch,

spruce and juniper rapidly advanced north across

the continent at about 500 metres a year.

Europe became cloaked in forest and echoed to

a new chorus of life.

The spring mating dance of the capercaillie...

a sure sign the seasons were in full swing...

with the trees, came new settlers who also found their niche here-

from tree climbers like pine martens to birds of prey...

all seeking out the small mammals sheltering in the forest.

Red deer, grazers of the open tundra, now browsed in the woods.

Around 10,000 years ago these early coniferous

woodlands were at their peak.

By then, the flanks of europe had also

undergone a radical transformation.

Sea levels had risen and risen...

by a 100 metres or more... defining the outline

of the continent as we know it today...

with around one and a half million kilometres of coastline.

One of the most impressive new coastal landscapes

of all lies in northern norway.

Here, deep valleys were scoured out by glaciers

and then drowned by rising seas, creating a network of fjords.

These waterways are as deep as the mountains are high.

Blessed by the nutrients and warmth carried here by the gulf stream,

they teem with life and remain ice-free all year round.

Each year, the north norwegian fjords lure hundreds of killer whales.

They come for the enormous shoals of herring that over winter here.

The impact of the gulf stream and the rising seas

is felt right across western europe, from norway all the way to ireland...

france... and scotland.

Pounded by the atlantic, this rugged coastline is home

to some unique concentrations of life.

Around 120,000 grey seals inhabit these waters...

...also exploited by otters...

in the british isles alone, some 6000 new islands

were born during the postglacial melt.

The remote craggy cliffs offer perfect nest sites

for birds like fulmars, guillemots, and gulls.

These are some of the most impressive seabird colonies in the world.

And because they're so inaccessible, predators pose little threat.

In the summer the skies come alive.

Along the northern rim of germany is a very different wildlife haven.

These are some of europe's youngest coastlands...

and a vital stopover for birds migrating up and down the east atlantic.

More than 2 million visit every year.

For waders they offer a gastronomic treat of

shellfish and worms.

But feeding here is always a race against time

and tide.

And - there's another drawback.

All this commotion attracts one of the fastest

and most agile hunters in the world.

The peregrine falcon.

After the last glacial period, these new coastal fringes,

with their prolific supply of food,

were also vital corridors for new arrivals,

making their way up the atlantic coast.

Here, from around 10,000 years ago,

stone age people began to find a foothold along europe's shores.

This was a brand new way of life...

a diet based almost entirely on protein-rich shellfish...

scallops, limpets, dog whelks and winkles.

And with food so readily available,

they had time to develop cultural pursuits...

making music and decorative jewellery.

While the northern margins of the continent remained a bleak place,

the interior was changing radically.

Unsuited to the warming climate,

the coniferous forests were now retreating,

replaced by seasonal, deciduous woodland.

A diverse mix of trees like hazel, oak, elm,

lime and beech spread their way north.

All sorts of different animals aided this re-forestation...

by over-stocking their winter stores.

For a time access to the interior

was only open to those that could fly or take advantage of waterways.

Fish like atlantic salmon moved upriver from the sea to spawn.

This was now a pristine wilderness

of endless forest broken only by rivers and lakes.

Soon the rivers would provide access to the forest.

It wasn't long before coastal dwellers began to head inland...

to find a wild new world to explore and exploit.

Mature silver eels were another enticing lure.

The most efficient way of catching the eels

was by intercepting them during their autumn migration to the sea.

People constructed elaborate basket traps

of stakes and wickerwork to divert the large shoals.

Eels provided them with a reliable

and highly nutritious source of food.

Large quantities could be kept alive or smoked for later.

While these corridors offered reasonably safe access

to the fringes of the forest,

the deep interior must have seemed a very foreboding place.

Impenetrable, gnarled and twisted...

...and roamed by dangerous predators.

But in time it would be conquered.

For now, as the climate released its grip,

a new force was on the rise...

one which was destined to tame

and transform europe more rapidly than ever before.