Original subtitles

Earth's great rivers...

..from source to sea...

..make extraordinary journeys...

CRACKING

..carving through continents...

..nurturing ancient civilisations...

..feeding and connecting life across our world...

ROARING

..from the mountains and deserts of the Nile...

..to the cities and mysterious swamps of the Mississippi...

..and the steaming waters and the secret worlds

of the tropical Amazon.

Great rivers are the lifeblood of planet Earth.

One river dwarfs all others.

The biggest on the planet.

The Amazon.

It flows through nine countries across one third of South America...

..sustaining the largest rainforest on Earth...

..supporting the world's greatest diversity of wildlife...

..inspiring vibrant cultures.

THUNDER RUMBLES

The Amazon's annual floods are so vast...

..they create what seems to be an inland sea.

Even today, it hides mysterious worlds.

To explore the unknown

and experience the mightiest river on Earth...

..the story begins with a single drop.

The glaciers of the Peruvian Andes.

Here, glacial meltwater tumbles down the mountainsides,

the start of a 4,000-mile journey to the sea.

On lower slopes, where the humid air from below

meets the cold, mountain atmosphere,

cloud forests thrive, shrouded in mist.

Tiny plants create hanging gardens on the branches of ancient trees...

..condensing the water vapour into sparkling droplets.

GENTLE PLOPPING

All around is the sound of the Amazon coming to life.

TRICKLING WATER

The Amazon is the greatest river basin in the world

gathering water from right across tropical South America,

amassing one fifth of the Earth's fresh water,

as it flows east across the continent.

Its 1,100 tributaries drain an area of nearly 2.5 million square miles.

And one remote stretch of white-water rapids

and deep, dark pools

is home to one of its largest and rarest predators.

GRUNTING AND CHIRPING

Giant river otters.

Some nearly two metres long.

This family are exploring a new territory,

a stretch they are keen to claim.

SPLUTTERING

Led by dad, the family follow his calls

with a chorus that is unique to their group.

PURRING

They are looking for a spot rich in fish.

Now, the parents can teach their young how to hunt.

It will be a testing time for the most inexperienced cub.

SQUEALING

GROWLING

Father coordinates the hunting party.

Because fish can evade otters in the deep water,

the family's best chance is to corral the fish

up against the bank.

This youngster has missed out.

Everyone seems to have a fish but him.

MEOWING

Luckily, the others are usually generous enough to share.

Which won't impress Father.

GROWLING

It takes three years for an otter cub

to master the complexities of fishing in these rivers.

The remote headwaters of the Amazon

have an unpredictable and dangerous reputation.

Many call currents and rapids like these "boat breakers".

And there are accounts of early European explorers

disappearing without a trace.

These upper reaches are home to legendary river monsters...

..electric eels capable of generating more than 500 volts...

..enormous pacus, some up to 25 kilos in weight...

..and giant anacondas,

amongst the largest snakes in the world.

Some of these Amazon headwaters are so inaccessible,

they conceal mysteries that are only now being revealed.

On the bank of one distant tributary,

the forest conceals a rare treasure.

A pool of crystal-clear water.

With strange, bubbling sand...

..this pool is in fact a spring.

Rising from deep underground,

the water is filtered...

..leaving it as spotless as an aquarium.

With such clean, pure water, it's a perfect nursery...

..tempting out of the murky river,

a pair of cichlids,

so new to science

that this particular species doesn't even have a name.

This couple are here to raise their family...

..a brood of 100 tiny fry.

Cichlids form strong bonds with their partners

and are as loyal to their babies as they are to each other.

This family seems to have found their perfect home.

But out here, danger is never far away.

Between the clear, spring waters and the murky main channel,

a unique feature forms.

A water wall.

It hides voracious predators like these freshwater Amazon barracuda

and a five-kilo wolffish.

They lurk, watching and waiting.

But the big fish seem strangely reluctant

to enter the clear water...

..for fear, perhaps, of being spotted and eaten themselves.

A well-armed stingray tries his luck.

Using natural camouflage,

they can hide themselves, even in these clear waters...

..setting an ambush from where they might hoover up

100 fry in one fell swoop.

Dad spots something...

..and defends his brood.

The stingray is sent packing.

These dedicated and brave parents will have to be ever-watchful,

shepherding their young until, perhaps, one day,

they are old enough and bold enough

to face the perils of the main channel for themselves.

The Upper Amazon has many strange and secret worlds

which teem with life.

But there is one remote river

whose waters are apparently devoid of anything living.

As dawn breaks, an ethereal apparition appears.

Wisps of steam snaking across the canopy...

..revealing below an Amazon tributary which boils.

Only recently mapped,

it's the largest stretch of thermal river anywhere on the planet.

At around 100 Celsius,

fish unlucky enough to stray into these waters will be poached alive.

Hot bedrock from deep within the Earth's crust

lies unusually close to the surface here,

heating and purifying the water...

..ensuring that this stretch of the river

has always been cherished by those who live here.

The Ashaninka people

have been visiting the boiling river for generations...

HE CHANTS

..and revere it for its healing properties.

Juan Flores is their shaman.

HE CONTINUES TO CHANT

TRANSLATION:

Juan and his family have developed

a deep connection with this precious place.

They've learned how to make medicine

from mixing these steaming purified waters

with plants from the forest.

HE CHANTS

TRANSLATION:

Many medicines used today across the world

have their origins in the rainforests.

Yet less than 5% of the plants here in the Amazon

have been studied by modern science.

The rest remain a mystery known only to the local healers.

This extraordinary river simmers for the next four miles

before it blows away from the last of the foothills,

down to the plains of the Amazon basin.

Here, the tributaries meet and the river channels swell...

..surging faster and deeper.

The strength of the currents

erode at the soft river banks.

But out of this destruction comes fresh opportunity.

SQUAWKING

Hidden treasure...

..which attracts green-winged macaws

who flock together to gather on the newly-exposed banks.

They have come to eat fresh clay -

which might seem strange - but there's a very good reason.

This particular clay is naturally rich in salt,

a vital dietary supplement.

Far from the ocean, and washed away by the Amazon's high rainfall,

salt is a rare mineral here.

So, the macaws bicker over the best deposits

creating one of the Amazon's loudest and most colourful spectacles.

SQUAWKING AND CAWING

These lowland rivers set off out across the plains...

..many flowing with different colours,

their waters tainted by the great variety of rocks and forests

through which they have passed.

Ultimately, they all join together

to create one gigantic muddy river channel.

The mighty Amazon itself.

This central stretch of the river is so wide and deep,

ocean-going ships can sail over 2,000 miles inland.

At its halfway point where it meets the inky-black Rio Negro

lies the Amazon's largest city...

..Manaus.

With a population of over two million people,

this city made its fortune in the late 19th century

from the riches of the river and surrounding rainforest...

..rubber, gold and minerals.

Today, the thriving markets of Manaus

depend on a constant supply of local produce.

For the last century,

this flamboyant city has built a reputation

as the Paris of the tropics...

..dominated by an extravagant opera house.

The people of Manaus depend on local farmers

like Edmar Fernandes da Lira

who grows crops on the fertile muddy banks of the Amazon

not far from the city.

TRANSLATION:

These are the good times for Edmar

but he must work all the daylight hours he can.

TRANSLATION:

The Amazon's banks here are very productive.

Three times a week, for eight months of the year,

Edmar carries 400 kilos of leaves down to the waiting boat.

TRANSLATION:

But time is running out.

These are some of the last crops

Edmar will be able to sell for months.

He must prepare for huge change.

THUNDER RUMBLES

Every year in November, the tropical wet season sweeps in.

Six months of rainstorms inject trillions of gallons of water

into the Amazon river system, transforming it.

THUNDER RUMBLING

In the mid-Amazon,

stretches of river can quadruple in width and rise by ten metres.

The port of Manaus has a harbour wall built to hold back the water.

Beyond the city, though, it's a different story.

Edmar's farm is submerged.

Because he has prepared,

Edmar simply shifts his attention to his stilt garden.

For the next four months, the only vegetables to grow on his farm

will be those above the flood.

And when the river does recede,

it leaves behind a fresh layer of sediment

which will fertilise a new season of planting.

But the floods can be very powerful

and living with them comes with huge challenges.

TRANSLATION:

In recent years, the Amazon has faced more extreme weather events.

Drier dry seasons...

..and even wetter wet seasons.

Within the last two decades, rainfall has become so intense

that the floods have been the highest since records began.

TRANSLATION:

The river that has previously provided

so abundantly for Edmar and his family

is now threatening to destroy their way of life.

For nature, the arrival of the annual floods

still bring incredible opportunities.

As vast tracts of land become completely submerged,

they create the Amazon's legendary flooded forests.

Almost 200,000 square miles of rainforest become inundated...

..creating a new home for countless fish

that shoal amongst the branches where birds once flew.

The Amazon has over 3,000 species.

Many breed in the flooded forests during high water.

Hot on their tails

come the Amazon's most revered and mysterious creatures.

SQUEAKING

Pink river dolphins,

known locally as botos...

..the largest river dolphins in the world.

A flooded forest of this scale creates new opportunities

and challenges.

Leaves from the forests stain the floodwater dark brown.

Sunken branches create an obstacle course

but botos have specialist equipment.

Like their ocean cousins,

their domed forehead, known as the melon,

allows botos to scan this submerged world using sonar.

As if that's not enough, botos have another unique weapon.

They are the only adult dolphins with whiskers.

These help pinpoint exactly where their prey is,

no matter how it twists and turns.

The Amazon's flooded forests

have existed for at least eight million years...

..creating a world so special and unique,

it's home to some of the most bizarre birds on Earth.

Hoatzins...

..whose unusual lifestyle sets them apart from other birds.

They feed almost exclusively on leaves,

a diet which has an unfortunate and gassy effect...

..leading to their nickname...

..stink birds.

During the flood season,

certain riverside plants burst into new growth,

the cue for hoatzins to breed.

But the new leaves attract spider monkeys, too.

Some monkeys can be a threat

and will often devour any eggs they find.

The hoatzins' only safety is in the most inaccessible branches

furthest out over the river...

..safe from the reach of greedy monkeys,

but now in danger from the floodwater.

THUNDER RUMBLES

Even near the end of the Amazon's wet season,

sudden intense storms can bring ten centimetres of rain in a day...

..drowning any nests built too low...

..and putting others in reach of river predators...

..like black caiman.

To make matters even more perilous,

hoatzin chicks are curious and more than a little clumsy.

Fortunately, they are not entirely helpless...

..as they are born with an unusual piece of climbing equipment...

..claws on their wings.

So even this little chick can clamber back up to safety.

At the peak of high water,

just under 300,000 square miles of the Amazon's flood plain

can be submerged.

Under this colossal weight of water,

the Earth's crust itself can sink by eight centimetres.

The floodwaters can remain high for three months

before they finally drain away down into the Lower Amazon.

River banks down here can be 15 miles apart.

Stretches of the Lower Amazon look more like a sea

and on its shore there are some spectacular beaches.

This region is often called the Caribbean of the Amazon.

Even though it's more than 300 miles from the ocean...

..every year, crowds of river people, Riberenos,

gather in the Lower Amazon town of Alter do Chao

for a seasonal celebration of the river.

As the party preparations begin in the town,

Sandro Branco and his grandfather

enjoy a moment of quiet before the fiesta.

TRANSLATION:

Sandro is right to be nervous as Alter do Chao stages

one of the most colourful and surprising river carnivals

in all of Brazil.

And Sandro is the lead man.

TRANSLATION:

CHEERING AND WHISTLING

Sandro is the star of the show, playing the pink boto...

..a legendary creature for the river people.

The local belief is that on the night of the full moon,

the boto dolphin turns into a handsome and seductive man

with a hat and a white suit.

Once on land, his challenge is to seduce young women.

BEATING DRUMS, CROWD NOISES

Despite the pressure...

..the dance has been a success.

TRANSLATION:

Sandro is the third generation of boto dancers in his family

but he's facing stiff competition.

The next wave of talent is hot on his heels.

TRANSLATION:

It's a celebration that has been going on for hundreds of years...

..showing just how the life of this great river...

..and the lives of millions that live along its banks

are inextricably intertwined.

MUTED CHEERING AND APPLAUSE

By the time it reaches the sea,

the Amazon River discharges around 175,000 tonnes of water

into the Atlantic Ocean per second.

This is more water than the next six largest rivers combined.

The Amazon's fresh water floats above the sea as a vast brown cloud

covering an area of up to 400,000 square miles.

Until recently, it's been very difficult to find exactly

what lies and lives beneath.

But today, the very latest technology

and the most advanced submarines are allowing scientists

to explore this last secret world of the Amazon.

In a dive 300 miles north of the Amazon's mouth,

the expedition is revealing that the river's nutrients

are fertilising the ocean's waters, creating a bloom of plankton.

It is hard to imagine that there would be life underneath this murk.

As the dive continues below the plume,

chief scientist Rodrigo Moura and pilot Allan Scott

discover something extraordinary.

Ah, I've never seen anything like this before, never.

A massive reef of colourful, rock-like algae.

Oh, look.

Look at the size of these guys!

Thronging with rich and varied marine life...

Angel fish. Heaven.

CHUCKLING

..under the dense plume of the fertile river water,

it turns out there is a hidden world.

An enormous algal reef more than 600 miles long.

And that's not all.

An underwater garden of giant sponges.

Some of the sponges are more than a metre across

and 1,000 years old...

..all feeding on nutrients which the Amazon has collected

on its incredible journey.

We don't see this every day, huh? No, not every day, this is special.

No other river on Earth is known to have the power

to shape such an extraordinary ecosystem out in the ocean.

Every dive is now rewriting the textbooks.

From its humble beginnings as a drop in the mountains,

the Amazon is a river like no other.

From its source to the sea,

it has forged its own path, created new worlds

and is so powerful and so vast,

who knows what other secrets it has yet to reveal?

Intrepid Brazilian film-maker Joao Krajewski

has spent the last ten years

filming and travelling right across the Amazon.

Over that time, he's been lucky enough to have close encounters

with many of its exotic and bizarre wildlife.

The Amazon is outstanding because of its size and diversity.

The river, gigantic.

You can spend your whole life exploring this region

and there will always be something different to see.

But the Earth's Great Rivers series

set him a new challenge to film Amazon wildlife underwater...

..an almost impossible mission

as the Amazon River is perhaps the muddiest.

However, its great size means it has 1,100 tributaries

each with its own distinct character.

Joao has heard of a region in the Amazon's remote south

where the water is said to be clear.

So, he and his wife Roberta, his diving partner,

prepare an expedition.

TRANSLATION:

So, this is a very special day

because it'll be the first scuba dive ever in this river.

This is a true dive into the unknown.

It was the first time that I actually see the underwater world.

I would say there's more than 100 species of fish

just in this little area.

Every single species is new for me.

But just because the water is clear, it doesn't mean it's not dangerous.

I was there comfortably having fun with my fish

and, all of a sudden, I saw this shape coming towards me.

It's a giant electric eel.

I can't lie, I was really afraid of them

because you don't need to be bitten or anything.

If you just touch it accidentally, it can zap you really, really bad.

They are not afraid of you at all, they just come and come.

HE GASPS

And some of them can give you a shock of more than 1,000 volts.

If you are in the water, you can drown, you can die.

The problem is that on a hot day like this,

the eels are looking for shade

and actively swim towards Joao.

ROBERTA SPEAKS

A bit tense, yeah.

They are curious. They are slow

but they can...

If you touch them, ugh.

It's unsafe for Joao to film them in the water,

so he needs to make a plan.

This is the Brazilian way, we call it gambia, improvising,

last-minute idea but it will work.

This is the final touch.

A very special one.

So, it should work.

These strange eels have a bizarre behaviour which Joao hopes to film.

Yay!

I got it!

That was a good one.

He captures the moment when an eel comes up for a breath of air.

The lining of their mouth acts like a lung.

This ensures the eels survive dry seasons when the water is shallow,

often very low in oxygen.

Wow, what a day. Phew.

As Joao explores the region further,

he comes across some locations which are a wildlife film-maker's

dream come true.

Very, very unusually for the Amazon,

he finds some springs where the water is as clear as gin.

Joao is hoping the pools will give him the chance

to film new behaviour.

And he is not disappointed.

It's not long before a new species of cichlid

invite him into their family.

Wow!

One of the springs is like an underwater garden.

There are more than 1,000 fish in front of me, I'm not kidding.

But though it looks beautiful, there is danger.

Black caiman patrol the murky waters of the main river.

They can be up to four metres long, and weigh in excess of 400 kilos.

Roberta acts as lookout.

I'm keeping an eye out for caimans because we never know,

like, there is one big one who lives right there

and we need to watch to make sure Joao is going to be safe.

Joao has no idea what is lurking in the gloam.

The dividing line is so clear -

you have dark in one side and crystal clear on the other.

I never thought it was so clear.

And just as Joao is on the boundary,

the ranger spots something in the river.

Heading straight for Joao...

..the largest wild mammal in South America.

A tapir.

That's a crazy tapir. I've never seen a tapir looking like that,

stay for such a long time in the middle of the river.

Look. It's swimming upriver now.

Tapirs aren't usually dangerous but it could attack a caiman.

It's a reminder that Joao is vulnerable when he's in the water.

I'll just get a close-up

and then we go upriver which is safer.

As well as filming underwater,

for the final phase of his expedition,

Joao is hoping to get really close

to one of the Amazon's largest and most secretive predators.

And one of the southern rivers, the Cristalino, might just deliver.

Joao has heard rumours that this area of the river

is home to a particularly approachable family of giant otters.

They're usually very shy,

so it's a real surprise to see an entire family out in the open.

Absolutely amazing, amazing.

I never expected that.

The whole family is right in front of us.

We are four metres away.

All of them here.

Unbelievable. In the middle of the wilderness.

HE LAUGHS

They even allow him to join their fishing trip.

Having earned their trust, Joao attempts to get even closer.

Another improvised camera rig means Joao can join them in the water.

GROWLING

Oh, I've never seen them do this, absolutely unbelievable.

Right in front of me and they're still doing it,

they're playing, out of the water, amazing, amazing.

So, although the sheer scale of the Amazon seemed so daunting...

..the mighty river revealed its secrets...

..giving Joao a window into its hidden underwater worlds.

Next time...

..the majestic Nile.

The world's longest river flowing from the equator to the Sahara...

..through astonishing unexpected worlds...

..bringing life to the driest parts of the hottest continent on Earth.