Imagine if you could halt the constant march of time.
...if you could slow it down... and speed it up.
Imagine if you could stop time... or even reverse it.
The world about us would look quite different.
Imagine no longer... come with us as we go on a journey through time.
The earth is full of surprises.
What is this sea creature doing on Mount Everest?
Why will East Africa end up under the sea?
And how did river crocs get stranded in the Sahara desert?
We can get answers, but ONLY if we play with time.
We will show you the hidden forces that build mountains and tear our world apart.
We will show you the planet as you have never seen it before.
When we sit down in front of the telly we aren't expecting the earth to move.
But the ground beneath us IS shifting.
You'd only notice it if you could travel through time,
if the sofa could become your very own time machine.
Over millions of years
the ground beneath your feet has gone through some extreme changes.
It is still going on - but on a massive time scale.
We'll travel through the past, present and future.
Get ready for a wild ride through time.
We are so wrapped up in the day to day that we don't even notice time passing.
We're taken aback when people change or
when we suddenly realize how much we've aged.
So it's hardly surprising we don't clock change in the wider world.
It's so creepingly slow we don't see a thing.
Hidden in this icy landscape there lies a powerful force that's shaping our planet,
but we only notice it when something extraordinary happens.
In 1950 a hiker in the mountains of New Zealand
discovered some large pieces of metal
under the icy foot of the Franz Josef Glacier.
The glacier is in the middle of nowhere, so how they got there was anyone's guess.
They turned out to be pieces in a very strange puzzle.
It all started six years earlier...
On October 29th 1943
a light aircraft took off on a sightseeing trip.
It was a tour over the icescapes of New Zealand's South Island.
The tourists on-board were to get a lot more drama than they'd bargained for.
Technical problems forced the pilot to crash-land.
The passengers were rescued
and even the wreckage was recovered,
all except a few pieces of fuselage.
It was these missing pieces that the walker discovered six years later,
melting out of the glacier.
But the REALLY strange thing was that they were found
over three kilometers from where the plane crashed.
How on earth did they move so far?
The only thing linking the two sites was the Franz Josef Glacier.
So what secrets could it hold?
Glaciers look solid and immovable...
But if you throw a fast forward switch they perk up.
They turn into dynamic rivers of ice.
Deep inside the ice it's way below freezing,
yet there's water racing through.
Its own massive weight and pressure causes the lower layers of ice to melt.
This meltwater acts like a smear of slippery oil
gravity does the rest.
These frozen juggernauts grind down mountains,
crumbling rock like biscuit crumbs.
This glacier might only move two metres a day.
But over six years that adds up to three kilometres...
...the same distance the plane parts travelled down the mountain.
Remarkably the plane has been put back together.
A long, drawn-out pause in its flight-path.
But nothing in the life of a glacier.
The rocky valley below tells an even longer story,
one that affects us all.
When glaciers melt back they reveal the way
they've clawed at the rocks underneath.
These marks read like a book.
They tell us how glaciers ebb and flow over many centuries.
To see the plot unfold we have to watch the Franz Josef glacier in action,
thirty thousand years ago.
Over this period it grew - not just down the valley, but out of the mountains.
This was going on everywhere.
Glaciers from Norway to Chile were advancing
because the world was freezing up.
This was the great Ice Age.
Just 20,000 years ago almost half of the land was covered in ice.
Today we're concerned about global warming,
but this could all be over-ridden by bigger changes...
which could send the glaciers on the march once again.
When we squeeze thousands of years into seconds,
glaciers spring to life.
But time travel also allows us to throw new light on age-old secrets.
The Ancient Egyptians left some stunning reminders of their wealth and power.
But when the sun set on their civilization they also left a huge mystery behind.
A grumpy camel ride can take us back to the heart of it -
to the Sphinx and the Pyramids at Giza.
We can only imagine what these immense monuments
would have looked like at the height of the Egyptian empire.
We've always assumed the sphinx was built at the same time as the pyramids,
but maybe it wasn't.
The Pyramids entombed the dead kings of Egypt.
There are good records to show how and when they went up.
What's missing is anything about the origins of the Sphinx.
No-one can even agree on how old it is.
There is now a shocking suggestion that this half-man,
half-lion wasn't started by the Egyptians at all.
But if they didn't build it, who did?
500 kilometres to the south of the sphinx
the desert is full of natural monuments that might offer some clues.
On a fine day it's hard to imagine how this magical place came to be.
It becomes easier when the wind gets up.
The wind picks up loose sand and catapults it across the landscape for miles.
It's like being in a firing range.
Each grain of sand becomes a tiny, stinging missile.
A single, blowing sand grain doesn't do a thing.
But combine it with eons of time and you have a force that can carve rock itself.
Believe it or not this is how these bizarre rocks were blasted into shape.
But when the wind blows from just one direction
the rock gets whittled into something even more distinctive,
something remarkably sphinx-like.
Did the force that created this also have a hand in creating the great sphinx?
In their minds, these tourists are re-visiting Egypt's heyday -
over three thousand years ago.
But if they really want to get to grips with the sphinx
they'd need to go back fifty thousand years.
They'd be transported in front of a single giant rock
outcrop jutting over the desert at Giza.
No pyramids to be seen.
The wind was already hard at work.
Travelling now through thousands of years of fast forward,
those tourists might watch the sand grains eating away at the rock -
sculpting that distinctive shape.
The early Egyptians may just have happened upon this rock
and been inspired to add some finishing touches.
They gave this rock a name and found it a job -
guard duty for the pyramids which were built behind it.
They added detail and dazzling paintwork.
And they made it part of their culture.
For thousands of years the Sphinx DID guard the pyramids of Egypt.
But those days are over.
The wind is a sculptor that never knows when to stop.
This monumental rock is now a shadow of its former self.
It needs high maintenance to fight the ravages of time.
The modern stonemasons at Giza work year-round to shore it up,
but in the end they are powerless against tiny grains of sand... and time.
Time-travel can show us the big picture.
What happens as huge natural forces change the shape of the world around us?
Everything can and does change.
Take the Sahara desert.
It would cover the United States of America,
but even something this big cannot be taken for granted.
Temperatures regularly peak at 50 degrees.
There are places where no rain has fallen for years.
And yet living things attempt to cross it.
The Paris-Dakar rally is one of the world's great endurance tests.
Swallows cross it when they fly from South Africa to breed in Europe.
Bikers do this for kicks.
But it's no fun-run for the swallows.
How did they end up with the journey from hell?
In the middle of the Sahara is a rock -
and on it are paintings which might tell us.
They were done five thousand years ago
and show animals that couldn't possibly survive in a desert.
Was this the scene from the artist's back door?
It is certainly not the Sahara we know.
To see for ourselves, let's go back five thousand years...
Unrecognisable!
This Sahara had vast lakes, forests and abundant wildlife,
where today you'd be dying of thirst.
It was like this when swallows began their inter-continental flights -
a much easier route.
But then, rather suddenly, it all went pear-shaped.
It began five thousand years ago
with a small shift in the way our planet orbits the sun.
Even a small change like this results in massive climate change.
Rainfall dropped off and this triggered a dramatic chain reaction,
which left plants gasping.
The swallows' migration was turning into an endurance test of its own.
In some places the change from forest to desert may have happened
in the space of just one hundred years.
That's why swallows still struggle across the Sahara.
They haven't had enough time to change their route.
It's the type of journey that sorts the men from the boys.
Something this small really needs the right stuff to get to the other side.
Their prize lies beyond the Mediterranean.
Here it is - the insect-rich meadows of Europe.
Swallows have a few short months swooping over the English countryside
and raising their young before they have to do the whole thing over again.
Their marathon journey back to South Africa is no less easy.
But time offers a glimmer of hope.
In the heart of the desert lies the Ennedi Gorge.
This is not just an oasis. It's a time warp.
Deep in its shade is a tiny remnant of those vast lakes
that once covered this region.
It's the only water for hundreds of kilometres.
And it shelters one of the most unlikely survivors of the Sahara's wetter past...
Nile Crocodiles.
They are playing a waiting game.
The Earth's orbit is changing constantly, like a pendulum.
It goes through cycles every 20,000 years, like clockwork.
This means that the Sahara regularly alternates between dry and wet.
If they can just hang on here for another 14,000 years,
they may get a proper lake to swim in.
And the swallows might have an easier ride.
As for the Paris-Dakar rally... well, it'll be a picnic!
We've travelled through thousands of years
to see the morphing of the Sphinx and Sahara.
But now we're going to shift up several gears.
It's time to fasten seatbelts.
We're accelerating into deep time - through millions of years.
Only then will we have enough time to witness the creation of the Grand Canyon.
It is one of the world's greatest natural wonders.
Visitors can be silenced by its sheer scale.
But it's almost impossible to get your head around
how long it's been in the making.
It's taken 5 million years and it isn't even finished yet!
The creator of this canyon is still at work -
a force that will take your breath away.
Enter the canyon at your peril.
The Colorado River at the foot of the canyon
will certainly get your heart racing.
But these rafters aren't in real danger.
The steady flow of even white-water isn't enough to carve out these walls.
This is the work of something much scarier.
A force that can really let rip through these narrow canyons.
It's these people who should stay on the alert.
The danger signs are written all over the walls.
These beautiful shapes have been sculpted by water -
a huge amount of it and at phenomenal speed.
But where is the water?
This place seems as dry as bone.
The Grand Canyon lies at the heart of the Arizona Desert.
Most of the year it doesn't rain at all.
But when it does you'd better watch out.
This is where timing comes in.
Timing is everything.
A single raindrop is nothing -
it's when they join forces that things get serious.
The ground is so sun-baked that the raindrops just don't soak in.
They glance off it and stream across the surface.
The thin desert soils put up little resistance -
the floods simply sweep up everything in their path.
From all over the desert the floods race towards the canyon.
And then they begin to carve downwards.
Tourist attraction becomes hellhole in a matter of minutes.
In 1997, eleven visitors were swept to their deaths.
That was one flood
but imagine if we could watch the effect of thousands
of similar cataclysmic floods over millions of years.
The Grand Canyon is a powerful reminder that the world can change,
not gradually, but in short, sharp shocks.
This is how one of the most terrifying forces on the planet is unleashed -
not in days or even hours, but in seconds.
The duration of an average earthquake is less than sixty seconds.
Seconds filled with utter terror.
They look like acts of God, but in fact they're not random strikes at all.
If we whip over to Wellington, New Zealand we'll see what's going on.
It's a city that seems on sure enough ground.
But not if we travel back to a precise point in time...
Nine fifteen on the night of January 21st, 1855.
At this moment Wellington is just a small town.
The coastline is made of steep cliffs,
which plunge straight into the Pacific Ocean.
The next few seconds were earth-shattering.
A violent quake heaved the whole of this coastline upwards.
As the cliffs rose, they pulled a whole new area of land out from under the waves.
The sun rose on a different landscape.
Where fish had swum and surf had pounded there was now dry land.
It was on this newly exposed land that today's city,
its airport and roads were all built.
But the 1855 earthquake was not a one-off.
By racing through centuries we can see
they've wrenched up the coast, over and over again.
There's a pattern.
And it's a pattern that's repeated in very particular places all around the world.
The earth's crust is not one solid piece of rock.
It's broken up - like crazy paving on a grand scale.
The edges of these slabs are constantly grinding,
and when they suddenly jolt past each other - that's an earthquake.
To live along one of these edges is asking for trouble.
Wellington sits slap, bang on one of the boundaries.
But then so do San Francisco, Tokyo and Istanbul;
millions of people sitting on borrowed time.
An earthquake is bound to hit them sooner or later -
there is no if here, it's when.
Within seconds these immense forces can tear open the earth's crust.
Over much, much longer time frames they can change the entire map of the world.
But how can we possibly look so far back into the past?
It's possible because some things can travel through vast amounts of time.
This fossil is the remains of a sea creature
that's travelled through 150 million years of earth history.
What it has told us about the past has rocked the way we see the world.
It's turned our view of this mountain upside down.
At eight and a half thousand metres, Mount Everest is so high
that a cruising jumbo jet would graze its wing tip on the summit.
One of the first attempts to climb
to the very top was made in 1924 by George Mallory.
When asked why he was doing it, he quipped, "Because it's there".
But what we now know is that it hasn't always been there.
And we know because this fossil tells us.
It was found high up in the Himalayan mountains,
but it's the remains of a creature that lived only in the sea.
These peaks are hundreds of kilometers from the nearest ocean,
so how on earth were these sea creatures left high and dry?
We need to go back 150 million years...
to when ammonites were the most successful creatures in the world's oceans.
The seas looked very different
but then we wouldn't recognize the map of the world, either.
It started to become more familiar about 100 million years ago...
...when a chunk of land ripped away from Africa.
That chunk was to become India.
If we watch at a million years per second,
India appears to race across the ocean.
At first nothing blocked its way.
But over the horizon lay a huge obstacle.
India was on a collision course with Asia.
In earth-time this was the equivalent of a motorway pile-up.
The force of impact thrust the seabed between them out of the water.
It's been hurled skywards ever since.
Everest, K2 and Annapurna are just part of a chain of wreckage
along this crumple zone.
They haven't been up here very long -
they're raw, new mountains and animals have only just moved in.
They may live on top of the world
but they're walking on rocks from the ocean floor,
and it's these rocks that contain the sea fossils.
The collision is far from over.
India is still ramming the mountains upwards.
The world's highest mountain is being forced northwards 2 centimetres each year.
Things have changed even since Mallory's first climb.
Everest is not there any more -
it's moved a metre away - over there!
We've whizzed through the past, but time doesn't stop here, with the present.
The earth's not finished yet!
Let's travel on - to see what happens next.
In the tiny African country of Djibouti
a maintenance crew turns up to repair a crack in the road.
This is not your average wear and tear.
This is a crack that allows us to peer into the future.
What they're about to shore up
is the start of the biggest crack on the face of the planet.
This is a crack that can be seen from space.
It runs from that small road in Djibouti,
widening out through Ethiopia and Kenya.
It then spreads through Tanzania and Malawi.
It ends in Mozambique, six thousand kilometres away.
It's Africa's Great Rift Valley, and it's remarkable not just for its size.
This long, cliff-bound valley provides a stage
for the biggest gatherings of wildlife in the world.
It looks rosy.
But the trouble is, the future doesn't look bright at all.
We know, because that Djibouti road crew at the north
end of the crack is never out of a job.
Every time they fix it, it ruptures again.
So what's pushing the tarmac apart?
Time to step back...
...back 30 million years...
That's half way between now and the extinction of the dinosaurs.
The world was then home to some strange beasts.
East Africa has no mountains, no volcanoes
just gently rolling hills.
But pressure was building up from below,
a force destined to change Africa forever.
A huge abscess of molten rock from the centre of the earth oozed upwards.
It stretched the crust under East Africa to breaking point.
Molten rock was squeezed out to form new mountains.
And in less than a million years Mount Kilimanjaro grew from nothing
to become the tallest peak in Africa.
Even today there's volcanic activity along the rift.
There's a string of lakes along the valley fed from water
bubbling up through the hot rocks below.
They're so caustic that flamingos have it all to themselves.
Periodic eruptions also come with the territory.
The eruptions are proof that the valley is still rifting apart.
It's an inconvenience, but nothing compared with what's going to happen next.
In around ten million years time
the crack will have become so wide that the ocean will breach in.
All the wildlife in the Rift Valley will be destroyed
and a new sea will be created as East Africa separates.
No wonder these guys feel overwhelmed.
But just because this seems a long time off, we shouldn't feel too safe.
Given enough time, something huge will rear its ugly head.
Something that could destroy us all.
It could be in a thousand years, a hundred years, ten years.
Or tomorrow.
Take a look at this showstopper.
It's lying in wait here... in Yellowstone National Park.
Yellowstone is famous for its hot springs and geysers -
where the earth's heat escapes as super-heated water.
One in particular is renowned for the precision timing of its blowouts.
Old Faithful.
It goes off every 90 minutes.
It's the ultimate visitor attraction -
a spectacular natural event that goes off on schedule.
But maybe Old Faithful is not so much loyal friend as a sinister watchman.
Each time it goes off, we could be 90 minutes closer to Armageddon.
Yellowstone is sitting over a ticking clock,
one whose beat is so slow that until recently no-one even knew it existed.
Yellowstone is astride one of the biggest volcanoes in the world.
It's a volcano that's over 70 kilometres across,
and potentially so lethal that it makes Vesuvius look like a roman candle.
The last three times, it exploded with such force that
its ash buried half of North America.
It doesn't go off very often - but so far it's followed a pattern.
The eruptions come at 600,000-year intervals.
620,000 years have passed since the last eruption.
So if it keeps to schedule, our time is up.
No-one on the planet would escape this big smoker.
It could trigger a chain reaction of volcanic winters and -
for humans - potentially fatal climate change.
Will it erupt soon?
Or is there some other unseen time bomb due to go off?
Only time will tell.