High above the clouds...
..there are lost worlds.
Unexplored...
..unforgiving...
..wildly unpredictable.
But here on the great mountain ranges of our planet,
life does exist.
Against all odds,
a few extraordinary animals and remarkable people...
..make their home in the highest places on Earth.
Soaring over the Andes Mountains...
..a South American condor.
It's on an endless search for food...
..covering 100 miles every day
on wings that span three metres.
Below, strange worlds appear.
Cloud forests, home to tens of thousands of species.
The planet's largest salt flats, two miles up.
Ice fields stretching 200 miles.
The Andes is our planet's longest mountain range,
made up of a huge number of astonishing hidden worlds.
The condor has to keep flying,
but for those below, each must adapt to their own world...
..every one an extraordinary island in the sky.
The Andes form the spine of South America,
stretching 5,000 miles,
three times the length of the Himalaya.
They begin at the continent's southernmost tip, Cape Horn.
The Andes rise out of the sea, 600 miles to the north of Antarctica.
Down here, ferocious winds hit the land at over 100mph.
The weather changes faster than anywhere in South America.
One moment, a storm is brewing.
The next...
..total calm.
To live in the Southern Andes,
animals must adapt to the constantly changing environment.
PURR
A puma.
She has three cubs and must raise them on her own.
Just four months old, they're always hungry.
She must make a kill every four days...
..whatever the weather.
Clear skies deliver a sudden, sharp frost.
The pumas have lost their camouflage in this white world.
Hunting will have to wait.
The cubs use the time playing.
Practice for when they hunt for real in a few months' time.
The winter sun soon burns off the frost.
And that changes everything.
A guanaco.
A relative of the llama, and at two metres tall,
the Andes' largest animal.
Now, camouflaged again, the pumas go unnoticed.
There's no wind to carry their scent.
But when it's this calm,
the slightest rustle could give her away.
Once a guanaco gets going, there's no catching it.
A wind from the coast brings yet another change in the weather.
Fog blows in and is trapped by the mountains.
Visibility drops to a few metres.
Sound has become muffled.
For an ambush hunter, it's perfect.
When the fog lifts,
it reveals the puma's prize.
The family can eat 15 kilos of meat in a single sitting.
Their lives depend on making the most of every opportunity
in the ever-changing Southern Andes.
This landscape stretches for over 1,000 miles,
up through Chile and Argentina.
To the north are different mountain worlds,
each with their own challenges.
And at the very top of Chile
is the strangest place in the whole of the Andes.
Surrounded by a wall of high mountains,
rain clouds can't reach the Atacama Desert.
40,000 square miles...
..the driest place on Earth...
..yet one remarkable creature is so well suited to life here,
it's found nowhere else on the planet.
A salt flat lizard.
His whole life revolves around water and trying to find it.
In this sun-warped world, mirages make lakes appear out of thin air.
This time,
the water is for real.
Meltwater from distant mountaintops flows underground
until it wells up here.
It seems like an oasis...
..except this water is saturated with salt leached from the rocks.
There's a secret to surviving in this world.
It's right in front of him.
Brine flies,
salt specialists.
They pass the salt out of their bodies,
leaving them sweet and juicy.
All the lizard needs to do...
..is catch them.
To get the equivalent of a teaspoon of fresh water,
he has to eat 400 flies.
This fly-ridden shoreline is a paradise...
..and that's the problem.
There's a new guy in town...
..and this territory isn't big enough for the both of them.
The defender puffs himself up.
Perhaps looking larger than life will make the intruder back down.
Owning a stake in this shoreline
is the difference between life and death.
Bad news for the intruder.
For the victor, the prize is an endless supply of flies.
200 miles to the north,
the remnant of a vast prehistoric lake scars the barren landscape.
Trapped by the Andes, the lake slowly evaporated,
leaving behind an extraordinary legacy.
3,500 metres up, hidden in the Bolivian Andes,
is our planet's flattest place.
The Salar de Uyuni.
The world's biggest salt flat.
4,000 square miles of nothing.
Except for 50 billion tonnes of salt.
The salt flat is the most hostile Andean world.
Nothing grows here.
The salt is five metres thick,
studded with countless polygons formed as the Salar dried out.
The scenery seems unchanging...
..but sometimes in late summer
a miraculous transformation takes place.
Sudden rains leave a layer of dead calm water
just a centimetre deep.
The Salar becomes a natural wonder.
The world's largest mirror.
80 miles across.
At night, the Salar is transformed again...
..into a 360-degree star scape.
This dazzling show is only possible
because the landscape is so perfectly flat.
Yet only 200 miles to the north, the Andes are staggeringly vertical.
Here, 160 peaks rise to over 5,500 metres.
This is the Central Andes.
A series of rugged worlds.
Once the heart of the largest civilisation
the Andes has ever known.
The Inca Empire.
Only 500 years ago, it was the greatest empire on Earth.
Machu Picchu was its finest royal estate.
The Incas ruled 10 million people scattered across the Andes.
They were masters of engineering.
Their granite blocks fit together perfectly.
Some weigh 14 tonnes, each hewn by hand and hauled into position.
Today, the Inca Empire is long gone.
But its challenging, rugged world remains.
The Apurimac River carves a 200-metre gorge
through the Peruvian highlands.
At Quehue, it splits communities in half.
But the locals are direct descendants of the Incas.
They've inherited the same language, the same amazing engineering skills.
In June every year,
they come together to harvest the hardy mountain plant,
Coya ichu grass.
Strong and flexible to cope with harsh mountain winds.
Perfect for construction.
Acalina Ruiz is 77.
Right now, every local household is busy making 70 metres of rope.
It's a real community effort.
Soon, entire villages gather inside the gorge.
The grass is about to play centre stage in a mountain festival passed down from the Incas.
THEY CHANT
All this work has one purpose.
A bridge has stood here since Inca times, linking the community.
Acalina has been using it since childhood.
But in the mountains, the bridge wears out fast.
Fresh Coya ichu grass will make all the difference.
THEY SHOUT
But first, they must cut free the old, worn-out bridge.
Now, a new bridge can take shape.
After three days of hauling and weaving, it's ready...
..and Acalina can visit the other side in safety...
..all thanks to a bridge made without tools.
Just two tonnes of mountain grass
and Inca ingenuity.
The Central Andes aren't just an obstacle for people.
700 miles to the north, in western Peru,
the mountains are so high they stop clouds from drifting past.
It creates a scorched world of dry forests where rain rarely falls.
It's 40 degrees.
Even in the shade.
This parched landscape is home to the Andes' most elusive animal.
Spectacled bear.
He can go five months without a sip of water,
just surviving on succulent plants.
Strong, long legs and curved claws are perfect for climbing.
And he has the secret to mastering this near-vertical desert.
On a far hillside, there's the telltale sign.
A single fig tree.
A spring wells up here.
It's created a refuge where mountain animals find shade...
..and life-saving water.
Little bears have to be wary -
this sanctuary is a magnet for other bears.
Best not to risk a fight with a big male.
Young bears move between oases, seeking a place to call their own.
There's only a handful of springs
in 200 square miles of high-altitude desert.
In time, bears make a mental map of every spring in their territory.
Some are nothing more than a cooling mudslide.
Others have magnificent bathing facilities.
Thanks to his amazing memory,
this bear can even enjoy a swim in a desert.
The remote worlds of the spectacled bear
may not be isolated for much longer.
Roads are gradually connecting the Central Andes.
Northern Peru is a maze of steep slopes,
deep canyons and rough tracks.
They're only for the bold.
In Vilcabamba, villagers rely on one man.
Some here call him a hero.
Glorioso has one of the world's most dangerous jobs.
He's the bus driver.
And this is the 12.58 to Lima.
Glorioso has been behind the wheel for over 50 years.
He started aged 14, driving trucks across the Andes.
It starts off easy enough,
dropping 1,000 metres in a series of switchbacks called the horse killer.
Every year, over 1,000 lives are lost on Peru's mountain roads.
For Glorioso,
it's just a normal day.
He's been driving this route for 12 years.
Mountain roads are so abrasive, his tyres last only ten weeks.
But the really hard part is further down the valley.
Not the place to meet oncoming traffic.
For the passengers, it's just the usual commute.
Nobody's in a rush.
As the local saying goes,
it's better to arrive a little late in this world
than early in the next.
And that's the secret to a long career as a Peruvian bus driver -
taking the mountains at their own pace.
Roads like this wind their way through the remotest corners
of the Central Andes, but some peaks will always be off-limits.
The Andes are the youngest of the great mountain ranges.
Deep underground, two colossal tectonic plates are colliding.
As the land buckles, the Andes are formed.
Mud boils where it overlies vast underground magma chambers.
As the chambers swell, the land above rises further...
..in places, by over two metres a decade.
Sometimes, magma pushes all the way to the surface.
There are over 200 active volcanoes spread across the Andes -
more than anywhere else on Earth.
An eruption can blast a billion tonnes of ash
13 miles into the atmosphere.
Tectonic activity has left a remarkable legacy
across the Central Andes.
The solidified remains of an ancient magma chamber
dominate Peru's Paron Valley.
A granite tower is a rarity in the Andes.
It draws pilgrims from all over.
When I came to the mountain it's like when other people go to the church and pray.
I feel the same connection with God.
All his life, Ivan Calderon's passion
has been for climbing in the Andes.
But today is his first attempt at scaling this tower.
La Esfinge, 1,000 metres tall.
When this route was first climbed 30 years ago, it took ten days.
Ivan and his partner Foucault are attempting it in just one.
This is big wall climbing
in the extreme.
Falling from the top,
it would take 22 long seconds to hit the ground.
Because this granite solidified so slowly
over tens of thousands of years,
it's packed with large quartz crystals...
..and that's the key to the climbers' success.
As coarse as sandpaper, quartz is good for grip, but skin-shredding.
Three hours in, Ivan's at an altitude of almost 5,000 metres.
There's only half the oxygen as at sea level.
His muscles are screaming.
And now he faces the toughest part of the climb.
Next, a sheer face polished smooth by ice and wind.
Oooh!
Ooh!
Ooooh!
Ooh!
Oooh!
Oooh.
I'm exhausted.
The air is so thin
and it's hard to breathe at this altitude.
Six relentless hours into the climb,
and Foucault takes his turn in front.
After ten hours, the summit.
All day for...just for this moment, you know, just to enjoy this view.
Wow.
Amazing.
Ivan and Foucault have climbed above the clouds to 5,300 metres.
Beyond them stretches a whole new world of extreme high altitude.
Peru's Cordillera Blanca, the white range.
Here, clouds roll in from the Amazon basin 200 miles to the east.
Because they are so laden with rainforest moisture,
they generate wet, sticky snow,
creating a world of colossal snow sculptures.
Cornices, made by snow blown over mountain crests,
thousands of tonnes teetering on the ridgeline.
The sticky snow clings to cliffs.
Flutings form where avalanches have gouged channels...
..and most mysterious of all - and a speciality of the Andes -
penitentes,
blades of ice,
each up to six metres tall,
formed by the sun carving troughs in the snow.
One of the great natural wonders of our planet,
four miles up and almost never seen.
One creature, though, makes a home
in the Central Andes' ultimate ice world.
Peru's Quelccaya glacier covers 15 square miles.
It's the largest expanse of ice in the tropics.
And yet, white-winged Diuca finches thrive here,
5,500 metres up.
Also known as glacier birds,
they come to Quelccaya to avoid predators.
And they've discovered the perfect place to raise a family.
The glacier itself.
CHIRPING
Two chicks are hidden safely inside.
The world's only glacier-nesting birds.
And this is the very first time
anybody's seen inside one of their nests.
At night,
it drops to -10.
But insulated in their nest,
it's not the cold that threatens them up here.
It's the sun.
The chicks don't have long.
In less than a month, their home will melt out of the ice cliff.
It's a race against time.
In places, Quelccaya is receding over ten metres a year.
Other nests have already fallen.
Finally, one chick is bold enough
to follow its parent into the outside world,
leaving its sibling all alone.
Now, the nest is beginning to collapse.
As a last resort, the parents cut back on feeding.
Perhaps a more hungry chick can be coaxed out.
Safe at last.
But the future for its species is less certain.
The air temperature up here is rising,
and Quelccaya's retreat is accelerating.
At current rates, Quelccaya will be 30% smaller in just 20 years.
The home of the glacier bird is slowly disappearing.
Each extraordinary Andean world has its own unique challenges.
It's a long journey from the fast-changing world of the puma...
..through the sterile salt flats...
..and across the rugged peaks of the Central Andes.
But on the journey from south to north, there's one final,
very different Andean world.
900 miles north of the Central Andes, on the Equator, in Ecuador.
BIRDSONG
Cloud forest.
Even 2,000 metres up, it's 15 degrees,
with lots of sunshine...
..and more rain than anywhere else in the Andes -
six metres a year.
THUNDER RUMBLES
It's the perfect recipe for life.
Tens of thousands of species jostle for space.
Almost 800 kinds of bird,
a sixth of all plant species...
..but intense competition makes living here tough.
It seems everything wants to eat everything else.
One way to survive is to blend in.
Stick insects mimic thorny cloud-forest plants.
Glass frogs go a step further...
..with translucent skin
..to soften their silhouette.
But there's one frog here that takes blending in to a whole new level.
A newly discovered rain frog,
only two centimetres long.
On the face of it,
he looks quite ordinary...
..but he has a trick up his sleeve that baffles biologists.
A trick to escape predators...
..like this eyelash viper.
Large eyes lock onto the prey.
He leaps for cover...
..and now his masterstroke.
He's growing three-dimensional camouflage.
His new shape, colour and texture blend perfectly with the moss.
The shape-shifting rain frog was discovered in 2014.
It's only known from 11 individual trees
in the whole of the cloud forest.
It's just one of many new species being found here every year.
There's so much hidden in this world that we're yet to discover.
In the Andes, our planet's longest and richest mountain range,
the cloud forest is surely the ultimate place for life
above the clouds.
The highest shoot in the Andes was to Quelccaya glacier in Peru,
at 5,700 metres.
The crew are hoping to capture
the first images of birds nesting inside a glacier.
We are packing up to go to the ice cap at last.
We're heading up to Quelccaya
after a week of acclimatising to the altitude,
and we've got to hike about five hours, then we should be there.
So it's exciting, and slightly scary at the same time because we don't
quite know what we're going to find when we get there.
Ahead of the crew,
a team of scientists is already at the glacier, looking for nests.
I'm out of breath already.
At this altitude, there's only half the oxygen compared to sea level.
I think I left my lungs down there.
We're checking our pulses quite often
and our oxygen levels, just to make sure we're not clinically dead.
193. 215.
That can't be right.
With blood oxygen levels dangerously low,
glacier camp is a welcome sight.
This trip has been nine months in the planning,
and the crew still don't know if the science team has found any nests.
Good to have everybody together.
Yeah. So I've got to ask, what's the news?
We found fledglings, we found one nest building.
Yeah!
I don't know about you, but my heart rate has just gone up a bit more.
It's very exciting.
With the promise of something to film,
the crew settle into camp
and prepare to spend their first oxygen-starved night
in temperatures down to -10.
It's half past seven,
I'm freezing cold,
trying to brush my teeth before the water freezes,
trying not to spit in the vicinity of Pete's strange tent contraption.
Good night. Night, Pete.
Sweet dreams.
It's about half five, six. I've just woken up
after a night of not really sleeping at all -
you're kind of out of breath the whole night,
as if you've just been doing loads of exercises.
But the real effort is just beginning,
as the team hike to Quelccaya.
The parent birds aren't around.
This ice climber
has less than an hour to install a nest camera
before they return from feeding in the valley below.
It's quite hard to watch.
It just looks so precarious.
The glacier's melting fast and is unstable underfoot.
I'll be pleased when he's down, put it that way.
Back on the ground, wires from the camera are connected to a filming hide.
So this is the moment of truth.
Everything should be plugged in, ready to go.
Oh!
And there we have a view
into the glacier bird's nest.
Look at that!
So you can see here, you can see
the little bit of fluff on the two chicks.
Brilliant - we've got a window into their little intimate lives
when their parents come in to feed them, see how the chicks grow.
What a privileged little view we've got.
This is the first-ever footage of a glacier bird nest.
But there is a chance the adults won't accept the camera.
If they're too wary to enter the nest,
the mission will have to be abandoned.
They just flew up, so they're 20, 25 metres but they're getting closer.
OK, so I can see the bird,
about three or four metres up to the right of the nest.
She's checking it out. It's a new feature in her environment.
Come on, be brave.
Yes, she's in there, she's in there.
Now she's in? Yeah!
Flying out. Right past the camera.
With the birds accepting the camera, the hope is that the team will now
discover exactly what goes on in the hidden nest.
Before this visit,
all that was known about the nesting of this species was from two nests
found the end of April in 2014.
This activity was previously undocumented
and will help to build a story
of why and when the birds are nesting on the ice.
Spencer was part of the original team that discovered the birds' unique behaviour.
His search for new nests even takes him underneath the glacier.
It's a little nerve-racking being under here.
A lot of ice over me and I know it's melting and actively moving.
If it starts to creak, run!
Science runs in Spencer's family.
His father Doug has been studying Quelccaya for years.
Since 1980, the glacier has shrunk by around a third.
Whether Quelccaya's here in 20 years, 50 years or 100 years,
it's pretty difficult to speculate,
especially given the increasing rate
at which we're changing the atmosphere.
It's a little bit of a race against time trying to salvage and understand
what's going on in these ice caps while they're still here.
Back in the hide, there is some good news.
So, after a week of waiting, we've finally seen one of the chicks fledge,
which is very exciting.
And now there's one chick left, looking a bit sad.
He's all alone for the first time in his life -
probably doesn't know what's going on.
We're hoping the parents can encourage it to fledge soon.
The chick's home will not last much longer.
Come on, little fellow.
It's not really quite ready to take the plunge.
Coming up, coming up to you, Matthew. Ready.
Oh, he's popped back in his nest.
He's just not up for it.
Ooh - chick's flying, chick's flying.
So we've been watching them and we've seen the snow melting away
little by little around the nest.
One day, the nest is going fall and slide down this cliff face.
Luckily they've managed to fledge before that happened so, yeah, good luck to them.
In this really harsh environment.
Which is too harsh for me.
I'm going to go down the mountain and get some oxygen.