ATTENBOROUGH: North Africa.
High in Morocco's Atlas Mountains,
Barbary macaques shiver in the icy cedars.
(CHATTERS)
The ancestors of these monkeys fled here from a disaster
that overwhelmed their homeland.
Now, trapped in this isolated corner of Africa,
there's no going back to the land farther south.
Even in this snowy refuge,
there's a reminder of what drove them here.
The unbridled power of the African sun.
Under its intense gaze, the snow can't last for long.
Melt water should bring life to the lowlands.
Hundreds of torrents cascade southwards.
But each is flowing towards extinction.
Just 200 miles south of the mountains,
the rivers are vaporised.
Life has been burnt off the land.
This was the apocalypse from which the Barbary macaques fled,
the sudden and unstoppable advance
of the greatest desert on the planet.
The Sahara transformed North Africa.
Today, it covers an area the size of the United States,
one-third of the entire African continent.
This is one of the hottest places on Earth.
The merciless sun,
a colossal 1 S-million-degree nuclear reactor,
blasted life from the surface of the land.
It still wreaks havoc.
A faint breath of wind can be the beginning of disaster.
(RUMBLING)
Nomads tell of entire villages being engulfed,
camel trains disappearing,
and people buried alive inside their tents.
(RUMBLING)
A sandstorm can be a thousand miles across.
It seems miraculous that anything can survive such devastation.
The Saharan apocalypse wiped out many creatures,
but today, some still cling on
in the lands around the margins of the great desert.
It's very dry here.
Some years, the rains fail entirely.
A lone Grevy's zebra.
He weighs close to half a tonne,
and can go for three days without drinking.
Like the macaques, his forebears were refugees from the advancing Sahara.
(RUMBLING)
The land is scrubby and dry.
(GRUNTING)
(NEIGHING)
But this stallion has claimed it as his own.
He's been waiting months for visitors.
Female visitors.
If they like his territory, they might stay a while.
It's his first chance to mate for a very long time.
(GRUNTING)
Hardly a success.
Perhaps his visitors are looking for a more impressive partner.
There's another setback.
The females were being followed.
A posse of young males - every one a rival.
It's time to separate the men from the boys.
(WHINNYING)
One by one, the stallion sees them off.
The females had ringside seats.
And his prowess has not gone un-noted.
Machismo gives way to tenderness.
Around here, you have to take every opportunity,
be it for food, for water, or for mates.
Female Grevy's are a fickle bunch.
The herd have decided to move on.
All of them.
The stallion may never see them again.
But there's a chance that one is now carrying his foal.
In this harsh land, that must count as a triumph.
The sun's power cannot, however, reach far underground.
Below, in stark contrast, conditions are stable and tolerable.
And home to one of the planet's strangest mammals.
Meet the naked mole rats.
These sabre-toothed sausages wouldn't last a day in the desert.
Special filming tunnels allow us to see
how well adapted they are to the subterranean life.
They can run equally well in both directions,
so tight space is no problem.
They have lost their fur.
And most bizarrely, they live in social colonies,
much like termites or ants.
After time spent digging, the workers come together to relax.
But one here is very different from all the rest.
Their queen,
twice as heavy as her subjects,
and not afraid to throw her weight around.
She is the mother of every worker in the colony,
and exists in a near-continuous state of pregnancy.
Even now, two dozen babies are pulsating within her swollen belly.
Just occasionally, one of her brood is raised differently,
a daughter becomes a princess.
Until now, this youngster's enjoyed a lazy, privileged life.
But not for much longer.
She has a destiny to fulfil.
The surface is a place where no naked mole rat can survive for long.
But a princess will risk everything to search for a partner.
The quest is urgent.
There's an enticing smell in the air.
A seductive scent draws her downwards, to safety.
She's sniffed out a partner.
He too is alone,
and eager to start a new colony in his lonely burrow.
Two months later, the princess has become a queen.
And a new tyranny begins.
Tough though they are, such refugees
living on the edges of North Africa
cannot survive in the heart of the Sahara.
And yet here, in southern Nigeria,
there are creatures preparing to journey
right across the centre of that great desert.
Barn swallows.
(CHIRPING)
They've spent the winter roosting in a forest of elephant grass.
But now, it is time for them to leave.
All two million of them.
They're tiny, each weighing the same as a couple of one-pound coins,
yet the journey to their breeding grounds in Europe
is over 5,000 miles long.
Ahead of them lies a vast death trap.
The Sahara is too large to go around.
The swallows have no choice but to meet it head-on.
It will take one of nature's greatest feats of navigation
to cross this lifeless wasteland.
A wilderness that stretches not just to the horizon,
but almost beyond imagination.
It's an immense blank space on the map.
In spite of the Sahara's reputation,
less than one-fifth of it is sand.
The rest is stone and wind-scoured rock.
The sun not only bakes the land,
it warps its appearance.
The super-heated air, rising upward from the desert surface,
distorts the distant scene.
A reflection of the sky shimmers on the sands,
a mirage.
The sun is an illusionist.
To thirsty travellers, a mirage can resemble a lake
which agonisingly recedes as it's approached.
And swaying camels coming to the rescue
transform into dry, spiny acacia trees.
To cross this confused, shimmering landscape,
many swallows will need to find real water amongst the mirages.
Even in the Sahara, rain does sometimes fall
and that is sufficient for plants to survive,
providing they have the right adaptations.
Rising from the sand, a dried-out ball of twigs.
In strong winds, it can travel.
This plant may have been dead for 100 years.
Yet its name suggests that all is not lost,
for this is a resurrection plant.
Around here, rain might only fall once or twice a year.
But if you're searching for decades, that might be enough.
Dead limbs absorb water and unfurl in a matter of minutes.
But the resurrection plant needs one more miracle.
(THUNDER RUMBLES)
Rain must fall on its branches
before they dry out and close up again.
Within hours, shoots emerge.
In just a few weeks,
they flower and develop seeds of their own.
Then, before they can grow any larger,
the sun kills them.
But their seeds live on, ready for when the rains return,
even if that is a century from now.
North Africa wasn't always so brutal.
Scattered across the Sahara are glimpses of life
before the apocalypse swept over the land.
In the north, a petrified forest, trees turned to stone.
Remains from a far distant, wetter past.
White sediments in the heart of the Sahara are the dried-out remains
of what was once the world's largest lake.
In the east, ruined cities hark back to a time of plenty.
And here, deep inside Libya, is Messak Settafet.
Carved here are hundreds of images of animals,
all drawn from life.
Ghosts from a greener time.
Remarkably, a remnant of this old North Africa survives.
Bou-Hedma in Tunisia is sustained by mountain rains.
It's a relic of the savannah that once carpeted North Africa.
The vast grassland vanished
when a shift in the Earth's orbit drove the rains south,
and in perhaps only a matter of centuries,
the Sahara Desert overwhelmed North Africa.
The evidence suggests this took place around 6, 000 years ago.
In evolutionary terms, that's no time at all.
And life has had little chance to adapt to this new world.
Only a few tough specialists
can cope with life amongst the dunes.
Camels are sometimes called ships of the desert.
But, like the swallows, they're really only visitors here.
These ships can certainly cross the Sahara,
but even they can't make their home in the harshest places.
Left to wander the desert by themselves, camels would not survive.
They depend on their human navigators to find oases and wells.
Saharan folklore is full of tales of caravans
that missed a well by a few hundred metres and disappeared.
This is the White Desert, in Egypt.
The landscape is littered with giant chalk pillars,
carved by innumerable sandstorms.
This glaring white oven is lethally hot.
Food here is almost non-existent.
But there's a rare gift from a passing camel.
The smell has lured dung beetles from miles around.
For them, this is manna from heaven.
One dung ball could provide enough food
to last this female beetle the rest of her life.
But she has a problem.
To keep it fresh, she must bury it in moist ground.
And that's not easy to find.
The temperature has already risen 10 degrees.
This lizard avoids the roasting sand.
Only 30 centimetres above the surface, it's significantly cooler.
The reverse-pushing technique is certainly the fastest way
to keep the ball rolling.
But it does have one drawback.
You can't see where you're going.
Disaster!
Stuck between two dunes.
The dung ball is twice her weight,
but the urge to keep pushing is inextinguishable.
Now, it's 41 degrees Celsius.
Soon, she'll be baked alive.
Her survival instinct, in the end, overrides her love for dung.
(WINGS FLAPPING)
Much of the Sahara is uninhabitable,
but there are rare places where there is some possibility of survival.
Places where, by strange chance, there is water.
Waw an-Namus is an extinct volcano.
From space, it's a remote, black scar on the Libyan Sahara.
Yet there are other colours here, colours rarely seen on the desert floor.
Blue and green.
Rain fell thousands of years ago when the Sahara was green
and percolated deep into the ground.
And here water from this vast, ancient reservoir rises to the surface.
These pools offer another glimpse of the Sahara's past.
Wherever there's water in North Africa,
living relics from this wetter time have a chance to cling on.
This oasis is fed by a hot volcanic spring.
Slightly away from the stream of near-boiling water,
it's cooler and fish can live.
These are Tilapia.
Hatchlings stick close to their mother.
There are other dangers here beside the scalding water.
Particularly at night.
The crocodiles are stealthy.
And the Tilapia are almost blind in the darkness.
In panic, they all leap to escape the hunter's approach.
But this female can't abandon her brood.
The crocodiles won't be thwarted. They, too, can leap.
With first light, the crocodiles lose the element of surprise,
and the battle is over for now.
The mother fish has survived, but where are her young?
All present and correct.
They spent the whole night sheltering in her mouth.
The contest will be repeated at sunset.
There is nowhere else to go.
Oases are always sought by desert travellers
but not all are as they seem.
This is the great Ubari Sand Sea,
in the heart of the Sahara.
These swallows have travelled 1,500 miles since they left Nigeria.
Their superb powers of navigation will eventually guide them to Europe,
but now they, and other thirsty migrants,
need to find a speck of blue amidst this ocean of sand.
(CHIRPING)
And here it is,
Umm al-Maa.
Here, too, ancient groundwater wells up to the surface.
(CHIRPING)
But the birds need to be careful,
for the sun has played a terrible trick.
This oasis is poisonous.
Intense evaporation over thousands of years
has left the water saltier than the sea.
As if to underline the horror,
the place is infested by vast swarms of flies.
(BUZZING)
But this plague is the birds' salvation.
The flies are filled with freshwater, filtered from the brine.
So, like a desert wanderer squeezing a drink from a cactus,
the birds get all the water they need from the flies' bodies.
More and more migrants join in.
Wagtails.
(SQUAWKING)
This is the birds' only stopover.
It gives them enough fuel to escape from the Sahara and Africa.
Away from an oasis, it seems remarkable that anything can live at all.
The temperature of the sands can exceed 70 degrees Celsius.
There's not the slightest trace of water left at the surface.
And when that happens, the Sahara itself cries out.
(CRACKING AND HUMMING)
Billions of sliding grains generate a hum
that echoes across miles of empty desert.
These are the Sahara's legendary singing dunes.
(HUMMING)
Over time, these avalanches add up.
If you watch the dunes for long enough, something remarkable is revealed.
One and a half years flash past in a matter of seconds.
On this timescale, the dunes are like a stormy sea.
An unstoppable tsunami of sand.
In this immense, ever-shifting landscape,
it's easy to see how a lost traveller could succumb
to what's been called the Sahara's only endemic disease -
madness.
Can anything survive the North African desert
when the sun is at its fiercest?
It's approaching midday.
A fringe-toed lizard is hungry.
He's on a stakeout.
Flashy scales reflect some of the sun's rays.
Nevertheless, the heat is almost unbearable.
His prey hasn't left home all day.
The lizard is the last animal still out on the dunes.
But even he can't take it anymore.
To survive longer, you'd need a spacesuit.
And in a way, that's what these insects have.
Silver ants' armoured skin reflects light.
They can tolerate temperatures that would kill any other land animal.
Even so, they can only survive for less than 10 minutes in the midday sun.
Time is precious.
The ants race to find food as soon as their predators go to ground.
They can't afford to waste a second getting lost,
so they spin to take a bearing from the sun.
They log every change of direction, every footstep
in order to know exactly where they are and where their nest lies.
Only four minutes to spare and they've found a victim of heat stroke.
A meal.
But it's going to take a monumental effort to get it home.
Three minutes to go and they're nearing their maximum temperature,
an astounding 55 degrees Celsius.
But there are already casualties.
One minute left, and they're not going to make it.
Something has to change.
The silver ant is the hardiest of all desert inhabitants.
Even so, it can only survive outside in the middle of the day
for a matter of minutes.
Now, the desert belongs to the sun alone.
The sun has scorched life from the Sahara.
And yet the vast desert it created is a source of life half a world away.
The advancing Sahara vaporised the world's largest lake,
leaving behind the silvery remains of countless microscopic algae.
In winter, the wind carries away 700,000 tonnes
of this mineral-rich dust every day.
It blows from here all the way to South America,
where, astonishingly, it fertilises the Amazon Rainforest.
A striking demonstration of the reach of this mighty continent.
Throughout its long history,
Africa has influenced the entire planet.
It was the cradle of a remarkable array of land animals
that spread across the globe.
And, of course, it was the ancestral home of all of us.
ATTENBOROUGH: This is the tale of two of the Africa team's
most challenging desert expeditions.
(ENGINE REVVING)
One focused on a minuscule creature with an incredible turn of speed.
The other on a subject so slow, to film it in action would take years.
(CLANGING)
In both cases, the Sahara would push crews to the limit
in pursuit of the perfect shot.
In Tunisia, the mission is to capture footage of moving sand dunes,
something that's never been tried like this before.
WRIGHT: The problem is that because the dunes move so slowly,
we're going to have to leave cameras here for about 20 months,
and that just means there's a huge potential for things to go wrong.
ATTENBOROUGH: And with filmmaking, if something can go wrong,
it usually will.
Two local shepherds, Amur and Nasser,
have volunteered to tend the equipment full-time.
The camera tower will be the tallest structure for as far as the eye can see.
And there are three other cameras at lower angles.
All this toil will yield surprisingly scant results.
WRIGHT: They've programmed the cameras to take one photo every day,
that's only 365 photographs a year.
Which, when you run it at normal speed, just over 14 seconds.
I think it's taken longer to explain what's going to happen
than the end result will actually be.
ATTENBOROUGH: The cameras are left to the mercy of the sun, wind and sand.
In the meantime, crews are shooting all across North Africa.
In Egypt, the challenge is to get into the world
of the most heat-tolerant desert animal
the silver ant.
They're really small, they're really fast.
Like, you're not too sure if you've seen an ant.
ATTENBOROUGH: The crew have three weeks to gather the footage they need.
SLOSS: We're going to try a tracking shot on this ant nest.
Moving forward towards it,
as the ants pour out of the hole in their millions.
ATTENBOROUGH: Not only are these insects super-fast,
they also keep antisocial hours.
BARTLAM: The thing is, we need to be out here
in the middle of the day to film these ants.
They don't do what they do when it's nice and cool
at 7:00, 8:00 in the morning.
WRIGHT: I can't remember ever being in a place
where the wind was so relentless and the temperatures were so high.
ATTENBOROUGH: The insufferable heat is not the only problem.
Dangers are everywhere.
(BARTLAM SCREAMING)
There's a really fat scorpion, it's really big!
One, two, three...
(MAN SPEAKING IN LOCAL DIALECT)
This might kill.
BARTLAM: - Yeah? - Yeah.
It's big and they have a lot of poison in his dart thing.
SLOSS: - What, that thing there? (BOTH SCREAMING)
BARTLAM: Oh, my god!
HAWASH: Don't touch it!
ATTENBOROUGH: The scorpion will be released
far, far away from the camp, in a shady spot.
No such luck for the team. They're back to work in the midday sun.
This is... This is too much.
This is crazy! This is crazy!
ATTENBOROUGH: Indeed.
The heat seems to have given Kat and Warwick a touch of Saharan madness.
SLOSS: The plan is to do an experiment,
to find out how fast these little ants can run.
BARTLAM: So we're going to lay this along the floor,
and hopefully an ant will run alongside it,
and we can film it at high speed.
And from that, calculate their... their speed,
and perhaps try and relate it to how fast that would be for a human.
Like me.
ATTENBOROUGH: Silver ants are expert navigators,
using the angle of the sun to calculate their position.
But for our team, even basic mental tasks are becoming a challenge.
SLOSS: Count a second.
See one running and then count a second, see how far it gets.
It's quite difficult to count a second, isn't it?
No, it's "one".
"One", yeah!
BARTLAM: There he goes.
He's gone 10 centimetres in four seconds,
but we're running at 500 frames a second,
which is 20 times normal time.
So, in fact, he's covered those 10 centimetres in...
We know that he does half a metre in one second.
Half a metre per second, yep.
- 50 centimetres in one second, roughly. - Yeah, yeah.
So, how many body lengths is that?
He's maybe doing five body lengths a second
if he's two metres tall, like I am.
BARTLAM: Are you?
Yeah. That's how much more than a normal man I am.
ATTENBOROUGH: Eventually, the duo decide that if the silver ants were our size,
they'd be doing 280 miles an hour.
They're one of the fastest sprinters in the animal kingdom.
No wonder we've been struggling to film them.
It does explain a few things.
Ant-letics!
Knowing the exact speed of the ants is all well and good,
but there's still a great deal of work to be done before the shoot finishes.
However, in Tunisia, there's no shortage of time,
and hopefully no news is good news as far as Amur and Nasser are concerned.
The final week in Egypt, and the crew seem to be adapting to life in the oven.
Practice is making perfect, and the sequence is coming together.
SLOSS: I think we've got some lovely shots.
Every single shot's been really hard-earned.
ATTENBOROUGH: But getting down in the ants' world
is now taking its toll on the kit.
It's running to stand still,
the business of blowing dust off these things.
(SPRAYING)
BARTLAM: Oh, no!
It's got dust in it!
(CRUNCHING)
Ooh, crunch.
SLOSS: I think these ants are stunning-looking.
Near-impossible to film, I think, because of the speed they had.
But, you know, I've come to love them over the days and weeks.
ATTENBOROUGH: With the sequence in the bag,
Warwick wants the final traditional sunset shot.
It's the best time of day to film sunsets, in the evening.
That's experience that tells me that,
I've been doing this for years. You learn these things.
Thanks to Warwick's experience, including sunsets, he and Kat
have captured the extraordinary life of the speedy silver ant.
Over a year later, in Tunisia,
it's time to take down the sand dune cameras.
Bonjour!
- Nasser. - Amur.
Hi. Hello again.
WRIGHT: So how's it been, has it been good?
It's okay, but two days ago, we have a little bit, small problem.
After surviving 600 days in the desert,
the small problem is that the cameras have been vandalised.
I'm really hot and bothered now, it's 40 degrees,
and someone's smashed the cameras.
Not been a good start to the day, to be honest.
ATTENBOROUGH: There's no doubt the dunes have moved.
But the question is whether the equipment has survived.
That is amazing. The camera's still here.
I guess maybe it just took them so long to get through the toughened plastic,
that they felt they had made so much noise
they were worried about the guards coming,
because they only sleep a couple of hundred metres away.
After almost two years of waiting, it's the moment of truth.
I'm going to find out, find out whether or not
the cameras have actually recorded anything.
It's just hugely stressful because it's never been done before.
ATTENBOROUGH: The footage is a surreal window into a secret world,
the private life of a sand dune.
(IN DISTINCT TALKING)
The Africa team struggled under the burning sun
and driving winds that are hallmarks of the Sahara.
They went home with an enormous admiration for the creatures
that spend their entire lives battling to survive in this brutal desert world.