Original subtitles

NARRATOR: Earth's great rivers...

..make extraordinary journeys.

Carving through continents...

..feeding and connecting life...

..nurturing culture...

..providing a place for adventure.

From the frozen wilderness of the Yukon...

..to the tropical heat of the Zambezi...

HIPPO GROANS

..and the magical, hidden worlds of the Danube...

..great rivers are the lifeblood of planet Earth.

In the heart of Africa

is a forest.

A sacred place.

The Lunda people call it "yambeshi"...

..the heart of everything.

Here, a clear spring

bubbles to the surface.

The source of a great river.

One day, hippos will wallow in its deep, dark pools...

..and elephants will wrestle with its treacherous currents.

It will carve its way through bedrock...

..and its waters will fill great lakes...

..and spread out to form the largest curtain of water on Earth.

For this trickle to become one of Africa's mightiest rivers,

it will need to overcome many obstacles...

..on its epic journey

to the Indian Ocean.

But everywhere it touches,

it will bring life.

This is the story of the Zambezi...

..Africa's wildest river.

From its source in the northwest of Zambia, the Zambezi travels

for nearly two and a half thousand kilometres,

through six countries, on its course

to the Indian Ocean.

Like many great rivers, its beginnings are humble.

And its destiny by no means certain.

Flowing down out of the forests of its birth, the Zambezi

starts its great journey.

But just as its waters are getting going, it runs into trouble.

Barotseland.

An endless flat plane in the far west of Zambia.

So flat, the Zambezi completely loses momentum.

And it's September, the peak of the dry season.

Its waters are evaporating under the heat of the African sun.

But it's just now that the Zambezi is vitally important.

Especially for the people that live here,

like cattle farmer Makalo Makaulo.

MAKALO: September is the hottest time in the year,

where everything is dried out.

I tell you we are suffering because we depend on water.

Here in Barotseland,

everything depends on water.

NARRATOR: Every day in the dry season

to keep his cows alive,

Makalo Makaulo must take them from the arid grasslands

to the Zambezi's life-giving waters.

MAKALOQO: Zambezi River,

it's like a father to me.

The father who feeds his children.

The parent of Barotseland is Zambezi.

NARRATOR: But as the heat intensifies,

the Zambezi's waters are receding...

..leaving dry, hot riverbed.

A challenging place,

whatever your walk of life.

IN OWN LANGUAGE:

NARRATOR: But there are advantages to the dry season.

GIFT IN OWN LANGUAGE:

NARRATOR: For schoolboys and cattle farmers alike,

life goes on through the dry season.

As it does for the wildlife here.

BIRDS SQUAWK

ZEBRAS BRAY

These vast plains are home to some of the greatest concentrations

of wildlife anywhere in Africa.

And this is their toughest time.

But the heat can only build for so long.

It's now October, and a change is coming to Barotseland.

Over 30,000 wildebeest are on the move.

WILDEBEEST GRUNTS

They are heading for their calving grounds in the south of the plains,

in anticipation of the rains.

A sign that six months of drought is coming to an end.

When the rain is coming,

everything is changing.

NARRATOR: In October every year

tropical rains push down from the equator, and spill

over into Barotseland.

This is what all the inhabitants have been waiting for.

MAKALO: So when the rains come, our hearts are feeling very happy,

because we are expecting good things to come.

I don't know how you even express it, because everything there, even

the nature of the land is changing.

NARRATOR: The rains are completely transformative.

A greening of the land over 10,000 square kilometres...

..that can even be seen from space.

My God, why can't this period be like that always?

NARRATOR: As the grasslands are revitalized,

they become a globally important wetland,

supporting 350 species of birds.

And finally,

the wildebeest arrive at their calving grounds.

Over just a couple of weeks,

all the herd's calves are born

to coincide with this time of plenty.

CROAKING

But the rains are having an even more dramatic effect...

..on the Zambezi.

It starts to flood.

GIFT IN OWN LANGUAGE:

NARRATOR: The people of Barotseland have always lived in tune

with the annual flooding of the Zambezi.

Larger villages are built on high ground,

so they stay dry during the flood.

But many smaller buildings

are designed to be submerged for a while.

Abandoned for four or five months until the waters subside.

The rising waters bring new challenges.

GIFT IN OWN LANGUAGE:

NARRATOR: Most children have to stop going to school in the wet season.

But this school has been built with flooding in mind.

Set on a mound of high ground,

it even has docks for the pupils to tie up to.

So long as they can brave the school run,

Gift and his classmates can keep

learning while the waters keep rising.

Cattle farmers don't have the option of staying in the floodplains.

They now take to canoes to swim their cattle

to higher ground.

But beneath the waters,

the land is being fertilised

by the Zambezi's silt.

So when the cattle return,

they will have some of the most

nutritious grass around.

The floods are not only good for the inhabitants

of Barotseland...

..the waters of the entire flood plain are now gathering

into one rejuvenated flow.

The Zambezi

is on the move again.

Heading out of Barotseland,

the Zambezi now turns east

where, for the next 500 kilometres, it will form the border

between Zambia and Zimbabwe.

Boosted by the water from upstream,

the Zambezi grows.

And, as it grows, it brings more opportunity for life.

The Zambezi is starting to look like a great African river.

As it flows over a series of steps in the bedrock,

it starts to gather pace.

And, in the distance, a cloud of mist is rising.

A hint of what is to come.

Right at the point where the Zambezi reaches its maximum power...

..the entire river flows over a cliff.

Nearly two kilometres wide...

..falling for over a hundred metres...

..500 million litres of water per minute.

So much water, it creates a plume of spray

that rises 500 metres into the sky...

..giving it the name of Mosi-oa-Tunya,

The Smoke That Thunders.

This is Victoria Falls.

The largest curtain of water...

..on Earth.

You would think it's a place to steer well clear of.

But there is temptation here.

A group of male elephants have come down to the edge of the river.

At this time of year, the islands right above the falls are lush

with tasty vegetation,

an elephant's paradise.

But to reach them is dangerous.

The Zambezi in full flood is a formidable force.

This is not the place to get swept away by the current.

But the lure of the islands is strong.

These males are prepared to take the risk.

ELEPHANT TRUMPETS

The further they go,

the stronger the current gets.

And now it's getting deeper.

They are forced to swim.

Immediately, the current starts to drag them downstream.

They need to reach an island

or they could get swept over the falls.

One by one, they find their footing.

ELEPHANT TRUMPETS

But for smaller elephants,

the danger is greater.

At last, they are all safely across.

And right away, they start feasting on their prize

of rich vegetation.

But elephants can eat 300 kilos of food in a day.

So they'll soon get through all the tastiest pickings here...

..and will have to take their chances with the Zambezi all over again.

Victoria Falls marks the next great transformation

for the Zambezi...

..as the entire river is swallowed up by a great chasm in the Earth.

Trapped in a channel just 25 metres wide,

the Zambezi now carves down through the rocky heart of Africa...

..forming sheer walls over 140 metres high.

This is the Batoka Gorge.

And it's here that the Zambezi conjures up another phenomenon...

..less well-known than Victoria Falls,

but just as unique.

The Zambezi Wave.

Surf perfection for those brave enough to try it.

MIKEY: It's crazy that you can bring something like surfing here.

NARRATOR: Mikey February is a professional surfer.

He's here, 1,000 kilometres from the nearest ocean,

to surf the Zambezi Wave.

MIKEY: It's once in a lifetime, and only a few people have actually done it,

and I think that's, you know, one of the most special parts

of actually coming here.

NARRATOR: Mikey has come to the Zambezi at a key point in the year.

As the dry season returns, over a period of three or four

months, the river changes again.

Victoria Falls starts to switch off.

Every year, the Zambezi goes through these dramatic cycles...

..with 50 times less water flowing over the falls when it's dry.

But it's as the water levels in the gorge start dropping

that conditions become just right for surfing.

When the water gets low enough,

it starts to interact with a rocky

shelf on the riverbed...

..and forms the Zambezi Wave.

A wave that stays in exactly the same place,

and breaks continuously.

But only lasts for ten days.

Even for a pro like Mikey,

the Zambezi Wave is not

to be taken lightly.

You have rocks, you have, you know,

hectic rapids and the water's moving

in such a different way to the ocean.

The fear factor is quite high.

NARRATOR: Because the wave is formed by a slab of rock just beneath the surface,

surfing it is dangerous.

And then there are the rapids.

Mikey needs to get out of the white water as fast as he can,

before he gets swept downstream.

He paddles for the pickup point on the riverbank.

But the current is too strong.

This is where his experience in the water comes in.

He keeps calm.

And the safety kayaker is immediately on hand to help

guide him out of trouble.

Mikey is keen to try again.

The Zambezi Wave is pretty much like catching an ocean wave

but in reverse, because the ocean is pushing you forward and the river

is obviously going the opposite way.

It's just a completely different experience.

Once you get it the first time,

then you actually kind of get a gauge

of what you should be doing.

And you kind of know exactly what to expect when you fall.

I did get scared surfing this wave.

It's like a balance of, like, surfing, survival mode,

surfing, survival mode kind of thing.

I think the more time you spend in the river and on the wave,

you learn new things about it.

The way it moves and noticing its, you know, little subtleties.

It's also so beautiful, you know,

obviously you get to surf this wave,

but you also get to appreciate the Zambezi and everything

that it has to offer.

NARRATOR: From the gorge, the Zambezi journeys on.

Winding its way through the fractured land along the border

between Zambia and Zimbabwe.

But it's about to shapeshift once more.

This time, at the hands of an entirely different force.

Kariba Dam.

Built in the 1950s,

it completely blocks the Zambezi,

and forces it to flow through its turbines to make electricity.

It took just five years for the river, held back

behind the dam,

to rise 100 metres.

Swelling up to form the vast Lake Kariba.

Over 30 kilometres wide.

280 kilometres long.

185 cubic kilometres of water.

So much water that it caused over 20 large earthquakes as it settled

down on the land beneath.

By volume, Lake Kariba is the largest manmade lake

on the planet.

But it has also become a haven for wildlife.

Along the lake's shoreline, rich grasslands have grown up.

And in the forests of drowned trees

formed by the rising waters

is a unique habitat.

Perfect for the Zambezi's most iconic bird.

The African fish eagle.

There are around 500 breeding pairs here.

Each pair mates for life...

EAGLES CRY

..the contorted shapes of the trees providing a platform

for their nests...

..protected by the crocodile-infested waters below.

The trees also provide the perfect vantage point

to survey the lake for prey.

On two-metre wings, they hunt for fish in the shallows.

This place is so good for fish eagles,

it has become their stronghold...

..their haunting call, the sound of Lake Kariba.

EAGLES CRY

The Zambezi is now at the halfway point on its journey

to the Indian Ocean.

As its waters break free of the great dam,

the river flows on.

And now it enters a lost world,

spreading out into a valley 50 kilometres wide...

..nurturing a vast wilderness...

..some of the richest wildlife habitat in Africa.

ELEPHANT TRUMPETS

It has also become world famous as one of the places to come

and watch wildlife.

This part of the Zambezi and its tributaries is dotted

with safari lodges...

..places where people come to meet the Zambezi's iconic animals.

But who's watching who?

This safari lodge has operated for many years,

and the wild animals are now used to people.

And there's one main attraction just beyond the lobby.

A wild mango tree.

Its fruit is ripe for just a short time,

right at the end of the dry season.

A mouth-watering treat when food iS scarce.

But it's not just baboons that have a thing for mangoes.

There are larger guests about to check into this lodge.

Elephants have been coming to this mango tree

from the river nearby for generations,

following ancient pathways that existed long before

the lodge was built.

One family in particular has learned that the lodge and its inhabitants

poses no threat.

Why go around?

When you can walk right through reception.

These are completely wild elephants.

But over the years, they have developed an understanding

with the staff here.

A trust passed down through elephant generations.

We've definitely developed that relationship and we've seen

youngsters grow into almost adults now over the years.

So it's... it's a beautiful relationship we have.

NARRATOR: This young bull probably first followed its mother

through here as a calf.

Now he is so relaxed,

he even takes time to browse the gift shop.

And check in at reception.

But soon, the lure of the mangoes is too great.

Trees like this are vital for the wildlife here.

Their roots draw water from deep underground,

so they can fruit even in the dry season.

An important source of energy and vitamin C.

And while the elephants are feasting,

the guests get a wild encounter of a lifetime.

When the elephants have had enough,

they quietly leave.

The same way they came in.

Straight through reception.

Elephants are big eaters.

But they also drink over 200 litres of water a day.

And for that, like all animals here, they rely on the river.

BIRDS SQUAWK

But the Zambezi is not only a place to get a drink.

For carmine bee-eaters,

the banks of the river provide the perfect place to make a home.

Their colonies can contain up to a thousand nests...

..each one dug into the sandy cliff face over a metre deep...

..where their eggs are protected from predators.

But outside the nest, the adults are vulnerable.

African fish eagles don't only live on Lake Kariba -

they can be found all along the Zambezi.

The skills that make them so good at catching fish

work just as well for birds.

BEE-EATERS SQUAWK

Hippos spend the hot days wallowing in the Zambezi's cool waters.

Schools of females live together in a territory ruled

by a single male.

And for the most part they are peaceful creatures.

Until the male's authority is challenged by a rival.

Then hippos turn violent.

HIPPO BELLOWS

In the safety of the river,

hippos are all-powerful.

It's as the sun goes down that they start to lose their bravado.

Hippos eat grass.

About 40 kilos every night.

They can't get that by staying in the river.

They may be huge - over two tons, but out of water

they become cautious.

So what are they nervous about?

As the night progresses...

..they travel further into the shadows.

Over five kilometres a night.

Not making a sound.

Soon, the hippos are peacefully grazing in moonlit meadows.

But they are being watched.

Lions.

A pride of lions patrol this stretch of the Zambezi.

They know that animals are moving to and from the river,

and the dark is their friend.

But would they be bold enough to bother a two-ton hippo?

It's when the hippos start heading back to the Zambezi

that they are most vulnerable.

Lions have formidable eyesight.

As the night gets darker,

they gain the advantage.

Now anything is fair game.

A female lion tries for an impala.

Alarmed by the chaos, hippos scramble for the safety

of the river.

But a young hippo is on its own.

That doesn't go unnoticed.

A male lion is on to it.

Just in time.

The hippo makes good its escape,

safe once more in the waters of the Zambezi.

As the Zambezi journeys on, it performs a last

great feat of transformation.

Flowing down on to the coastal plains of Mozambique...

..it spreads out into countless sinuous branches...

..forming a great triangle that reaches all the way

to the Indian Ocean.

The Zambezi Delta.

But this last chapter of the Zambezi's journey

is haunted by the past.

From 1977 to 1992,

this place was ravaged by civil war.

The human cost was immeasurable.

And it had a devastating effect on wildlife.

DOMINIQUE: During that war, wildlife was killed for the meat,

but also be killed for the ivory, for example, elephants,

everything just declined drastically.

NARRATOR: Dominique Goncalves is a Mozambican conservationist who's passionate

about forging a brighter future for the wildlife here.

She is part of a team tasked to go into the heart of the Zambezi Delta,

to find out what has happened to the wildlife

since the devastation of the war.

Dominique is an elephant specialist.

Her plan is to put satellite collars on key elephants

to understand their movements.

The first step in protecting all the wildlife of the delta.

If you protect the area that an elephant uses, you're also

protecting a huge area that many, many other species are using.

NARRATOR: But first, she has to find them.

The Zambezi Delta is vast —

eight thousand square kilometres.

Once, the Delta was world-famous for its extraordinary

wealth of wildlife.

Great herds of elephant, and the largest numbers

of buffalo in Africa.

Since the civil war, few studies have been conducted here.

So little is known about what is left, but after just half an hour's

flying, there's an encouraging sign.

Elephants.

DOMINIQUE: You really have to assess which individual we can work with.

So you have to think about the age and if it's a female, is she very,

very pregnant or not? If she has a young calf or not.

So you don't want to put an extra stress on her.

NARRATOR: The dart contains a fast-acting sedative.

And by the time the helicopter has landed,

the elephant is already asleep.

A quick check on its breathing,

and they get to work.

They must work fast.

Though the elephant is sleeping peacefully,

the quicker they are, the quicker it can return to the herd.

While the vet is fitting the collar,

Dominique gathers as much information as she can.

This is a rare opportunity to study these delta elephants.

Blood samples...

DOMINIQUE: Her feet is very small.

NARRATOR: ..foot size,

and getting a record of what it's been eating is a crucial

but less glamorous part of the job.

All completed in just 15 minutes.

SNORING

Snoring!

NARRATOR: A final shot reverses the effects of the sedative.

They now have just a couple of minutes to get airborne.

To encounter elephants so early in the trip is a hopeful sign

that good numbers are surviving in the delta.

In the next few days, Dominique successfully collars six elephants

from different herds.

And straight away, the collars start to deliver results.

She can see exactly where each elephant and their herd travels.

What space they need for socializing, feeding

and avoiding people.

Travelling the delta with their satellite collars,

Dominique's elephants are providing crucial hard data,

and are starting to map out the space that she hopes will

one day protect all the wildlife of the delta.

Even in such a brief visit,

there are tantalizing glimpses

of the life the delta could hold.

A great herd,

many hundreds of buffalo -

an echo of the legendary herds that once roamed here.

And a vision of what this place could be.

Here, where the Zambezi River

finally comes to the end of its journey.

DOMINIQUE: The Zambezi River is extremely important.

Not only in terms of biodiversity and nature,

but give us culture,

give us, you know, livelihoods,

give us many things.

Perhaps without it, it wouldn't be the same.

I think that's the thing that makes us all so proud to have the Zambezi,

one of the greatest, biggest rivers in Africa,

to just finish here, next to home.

NARRATOR: From a trickle of water in a far corner of Zambia...

..this great river has overcome many obstacles on its

2,500-kilometre journey.

The heat of the African sun...

..the rugged geology at the heart of the continent...

..the demands of a modern world...

..but wherever it flows, it brings life and opportunity.

No more so than here at the end of its journey...

..as the waters of the Zambezi

are finally carried away

by the Indian Ocean.

One of the biggest challenges for the Earth's Great Rivers team

was to film professional surfer Mikey February riding

the Zambezi Wave.

Timing was key.

This unique wave only appears for a few days each year...

..when water levels rise and fall with the rains.

It's also incredibly remote,

and dangerous to reach -

down steep, jagged cliffs

and through some of the most ferocious rapids

on the planet.

It's been quite the logistic nightmare, maybe, to organise.

We've had to postpone the shoot a few times just because the river

water levels are dropping, but they're not

dropping quickly enough.

And there's such a small window to sort of aim for,

for a wave that's surfable for Mikey.

NARRATOR: But the team decide tomorrow is their best bet to head off

in search of the wave.

And to get everyone there safely are

the Zambezi's most experienced river guides.

This one as well.

LEWIS: We've got four cameras, two drones, all the batteries, accessories,

all the cards.

There's a lot of expensive kit

that could end up at the bottom of the Zambezi.

NARRATOR: It's an early start,

and the team head to the edge of the gorge.

We're going to go down to the gorge now.

Please don't fall, don't slip, we're going just on ladders, so...

NARRATOR: Lead river guide Sean

briefs the team on the treacherous 100 metre-descent ahead.

It's an almost vertical drop down sheer rock,

and along rickety wooden ladders.

SEAN: All good in the hood? - Yeah.

Has anyone fallen? — All the time.

All the time!

SEAN: It begins.

MAN WHOOPS

NARRATOR: Lewis is the first to follow the guides down.

So far, so good.

Actually terrified.

But we must push forward.

NARRATOR: The last thing the crew needs now is a twisted ankle or worse.

OK? - I'm OK.

NARRATOR: The team make it down to the Zambezi.

Actually never been more happy to get into a raft.

NARRATOR: But the journey to find the wave has only just begun.

Precious cargo loaded.

Time to rock and roll. Let's go!

One, two, three!

NARRATOR: At first, all seems calm, but turbulent water lies

just around the corner.

And the river starts to come alive.

The mighty Zambezi throws everything it can at them.

Whoa, whoa, whoa, whoa!

NARRATOR: Suddenly, the raft hits a violent swell,

and sends camera operator Kevin hurtling into the rapids.

KEVIN YELPS

NARRATOR: He must get out quickly before the river throws him

into the rocks or drags him under.

But he's in safe hands.

Thanks to the quick reactions of the guide, Kevin's pulled

back on board.

MAN WHISTLES

And the team finally make it

to the Zambezi Wave.

Months of meticulous planning went into arriving

at just the right moment.

But now it's all up to Mikey.

MIKEY: It's so scary, and it's so, you know, sort of dangerous.

When you see a photo of the river, when it's super low,

you can actually see the rock that it actually breaks

off of, and it kind of plays on your mind.

You know, you obviously have to wear a helmet,

and then you also have to wear a life jacket.

In the ocean, you're just wearing a wetsuit or board shorts

or something - you definitely feel out of your comfort zone.

NARRATOR: But that's not Mikey's only concern.

MIKEY: Crocodiles, what's the situation?

So I mean, they're definitely here, and we can't discount them.

The danger zone is actually just this pool.

They don't like the fast-moving water.

So I think once you get

into the rapids, you're 100%, it's really just this area.

But I mean, we've all been watching, we've been looking, we've spoken

to the fishermen and they haven't seen crocs here for ages,

so I think we're good.

LEWIS: Go on, Mikey!

MAN YELLS

THEY CHEER

NARRATOR: To get here at just the right time, Mikey and the team

have descended cliffs,

and navigated white water rapids.

But in return, they experienced an entirely new side of one

of Earth's great rivers.

MIKEY: Everyone's got a different relationship with this river,

and surfing that wave is mine.