Human Planet

Only one creature has carved a life for itself in every habitat on Earth.

That creature is us.

All over the world, we still use our ingenuity to survive in the wild places,

far from the city lights, face to face with raw nature.

This is the Human Planet.

Humans have always been drawn to rivers.

Rivers flow through every environment,

bringing us the essentials of life -

fresh water...

...food...

...and ready-made highways.

But what rivers give, they can also take away.

They can flood,

freeze

and sometimes disappear altogether.

Rivers force us to take great risks.

These are remarkable stories of survival

from the most unpredictable habitat of them all.

It's the monsoon season, and the mighty Mekong,

Southeast Asia's greatest river, is in full flood.

Between Cambodia and Laos,

the Mekong current creates the widest rapids in the world.

The Khone Falls are great for fishing, but also very dangerous...

...as Sam Niang, a local fisherman, knows all too well.

Migrating fish get trapped here, waiting to get up the rapids.

Sam Niang has to risk his life to catch them.

He has a family of seven to feed.

He starts by fishing from the riverside, near his home.

During the monsoon, the Mekong swells to 20 times its normal volume,

which brings more fish, but makes them much harder to catch.

After a morning, his net is still empty.

There is another option - an island out in the main rapids.

But to get there, Sam Niang must take his life into his hands.

In the dry season, he built a high wire across the rapids

out of old cable and bits of rope.

At this time of the year,

these rapids have nearly twice the flow of Niagara Falls -

more than 1 1 million litres a second.

He makes it to his favourite fishing perch.

Turbulent currents corral the fish,

and Sam Niang soon lands his family's supper.

Though the fish are plentiful here,

the most he can carry back is a few kilos at a time.

Any more, and he might lose his balance.

Today, Sam Niang won his battle with the Mekong.

Tomorrow, to keep his family fed, he'll have to fight it again.

It's not just the power of water that makes rivers dangerous.

It's their erratic nature too.

Reading a river correctly

can mean the difference between life and death.

The Zanskar valley is a hidden world on the edge of Tibet,

in the heart of the Himalayas.

In winter, it's cut off by snow.

All roads in and out are impassable.

Stanzin needs to get his two children to school,

but the nearest school is 1 00 kilometres away,

and the only way to get there

is to walk down a frozen river.

It's a six-day trek, so dangerous it's got its own name -

the Chadar - the blanket of ice.

They'll have to brave sub-zero temperatures,

avalanches and freezing water.

Term starts in a week.

It's time for the school run, a formidable trip for 1 1-year-old Dolkar.

Dolkar's 1 4-year-old brother, Chosing, is coming too.

The family prepare for the journey ahead.

Their mother has knitted them thick woollen socks to protect them.

The brother and sister depend on their father's courage and skill.

This has to be the most perilous school run in the world.

The spring melt seems to have started early, which worries Stanzin.

Stanzin has to make sure the ice can take their weight.

And his expertise is tested immediately.

The danger is not only underfoot. There's another threat - avalanches.

Seven days ago, an avalanche killed a man on the Zanskar river.

The unusual spring sunshine has brought another problem.

The river's current has already melted the ice.

Stanzin has to find a way past the barrier.

The only way around is a narrow ledge.

The ledge is barely 20 centimetres wide and covered with snow.

There's a ten-metre drop to the freezing river below.

The ledge ends with some metal pegs to climb down.

Chosing makes it.

Now it's Dolkar's turn.

They mustn't delay.

Night is falling fast, and the temperature will plummet to minus 30 Celsius.

Luckily, Stanzin knows a cave nearby.

The children need their sleep.

The most dangerous part of the Chadar is still ahead.

It's not all hard slog.

But Dolkar's fun can't last.

As the smallest, she's the first to feel the cold.

She starts to lag behind.

One little girl on a melting ice river,

among the greatest mountains on Earth.

Now for the final leg.

The melting ice has left just a tiny shelf.

It's thin. Stanzin is worried it won't take their weight.

As he advances, the ice starts to crack.

With the ice weakened by Stanzin's weight,

the children have to brave it on their own.

Dolkar's made it, now for Chosing.

Thanks to their dad's expertise, the children have survived the Chadar.

Six days out on the ice river.

The Himalayan town of Leh, journey's end for the children.

They rush straight to the school.

There's just enough time for a goodbye.

Stanzin now faces the return journey on his own.

Melting river ice doesn't just make travelling harder.

When frozen rivers break up, tonnes of ice start to flow,

a potential disaster, even in the heart of a modern city.

In the Canadian capital, Ottawa,

spring melt turns the Rideau river into public enemy number one.

The danger point is a footbridge on a frozen waterfall...

...a bottleneck where the Rideau flows into the Ottawa river.

It's late February, and the ice is melting here too.

Ice blocks are in danger of forming a dam,

which might lead to devastating flooding.

A natural threat that needs a daring human solution.

Meet the ice-dam busters!

Theirjob isn't just to predict nature,

they have to beat it!

There are thousands of tonnes of ice behind the bridge, up to a metre thick.

The team needs to break it up to keep the river flowing.

Stage one - cut the ice into long strips.

They're still too large to flow under the bridge, so, for stage two,

the team uses a more persuasive force...

Now!

...hundreds of kilos of dynamite.

Hup!

Bite-size pieces now flow easily under the bridge and over the falls.

The centre of Ottawa is safe for another year.

The world's largest rivers bring the most danger to our lives.

Their floods can be devastating.

They often happen without warning,

and there's nothing we can do but try to escape.

In Bangladesh, tens of millions of people

can be displaced when the Ganges and her tributaries burst their banks.

The river is so strong, it regularly changes course,

brushing land aside as it goes.

A month ago, Mohamed Jaleel's village was 1 00 metres from the bank.

Today, his house is about to be swept away.

He and his neighbours have only minutes to move his home.

The rest of the villagers look on, helpless,

as the rising river obliterates their land.

In South America, floods can be so huge

that the entire year has to be spent planning for them.

In the Amazon basin, one mother prepares for the rising waters.

Jarnia lives by the Rio Negro in Brazil.

It's November, the dry season, the time of plenty.

Fish are so easy to catch,

she even has enough to feed the local river dolphins.

But in six months'time, when the flood water invades,

all these dolphins and the fish with them

will disappear into the flooded forest to breed.

When the fish are gone, feeding her large family will become a nightmare.

Surviving such hard times means thinking ahead,

and Jarnia has a four-stage plan.

Stage one is collecting turtle eggs six months before the floods arrive.

River turtles lay thousands of eggs in the dry season beaches,

which they leave to hatch.

Turtles are a reliable source of protein when the waters rise,

so these eggs are precious.

Back in the village, it's time for stage two.

Jarnia reburies the eggs in her turtle nursery.

In the wild, many eggs would be eaten by animals...

...but here they'll be safe.

By March, four months later, 3,000 eggs have hatched.

It's stage three - release day!

It's time to release the babies.

But will enough of them survive to feed the village in the floods to come?

It's June, the height of the rains.

The river rises seven metres.

Jarnia's village is transformed.

The forest is flooded,

and the nearest dry land is more than six hours'rowing away.

Jarnia's family is now marooned by the greatest annual flood on the planet.

Time for the final stage.

Jarnia and her sister Dora prepare to go turtle-hunting.

Jarnia's husband, Francisco, makes them a turtle-hunting spear...

...and then the two sisters set off in search of food.

Will their hard work bring dinner to the table?

At first, it's not looking promising.

Then Jarnia spots one.

Her preparation's paid off.

She'll be able to feed everyone.

Jarnia's foresight has pulled her family through another difficult flood.