Across our planet there are a few awe-inspiring places
that just take your breath away.
We call them natural wonders.
And for the people who live in them,
these places pose extraordinary challenges.
On the Earth's greatest waterfall, four brothers' lives
depend on a journey to the very edge.
In the planet's biggest river delta, desperate men face killer bees
and man-eating tigers in a search for golden treasure.
On the world's largest grassland,
a boy's future rests on the outcome of a single race.
And in our planet's richest ocean reef,
a guardian must hunt down a giant...
..in order to save it.
This is the story of these wonders,
and of the people fighting to survive...
..and even triumph...
..in these astonishing places.
Seen from space, there are some wonders which stand out
because of their scale.
They are the largest, the widest, or simply immeasurable,
and these vast wonders also push their inhabitants to the limits.
Deep in Southern Africa, the mighty Zambezi river.
Over five million years, it's worn away a tiny crack in the ground...
..and created this.
Victoria Falls.
Plunging 100 vertical metres,
this natural wonder is higher than Niagara and twice as wide.
Victoria Falls is the largest curtain of falling water on Earth.
And unsurprisingly,
the very edge is one of the most dangerous places imaginable...
..to fish.
But this is the torrent the villagers of Songwe,
15 miles away, will need to brave.
Village elder Josephat Chuma will lead the expedition.
It's dry season,
and the local village fishing spots are fished out.
But Josephat believes fish can still be found
where the water is fast-flowing,
so he will lead his three brothers to the edge of the falls.
To reach their destination, the brothers must face many dangers.
First, they have to cross a creek infested with crocodiles.
They make it across.
But now there's a bigger threat.
During dry season, elephants come to the river
from the now-arid plains that surround it.
They are territorial and volatile animals.
ELEPHANT TRUMPETS
Two years ago, Josephat's brother Mateyo saw his friend killed by one.
ELEPHANT TRUMPETS
ELEPHANT GROWLS
They hold their nerve and slip past.
But beyond the elephants, there's a danger greater than any animal.
The torrent itself.
Josephat knows the best place to fish is a rocky outcrop
just metres from the edge of the falls.
At peak flow, eight million gallons a second rush over it.
There is just one narrow route through the river,
where the current should be slack enough to wade.
If they stray a few steps either side,
the water could sweep them over the falls.
And two of Josephat's brothers can't swim.
Halfway across, the brothers freeze.
For most of the year, access to this outcrop is impossible,
but during the dry season, the water level drops just enough to
open up the one route the men took to get here.
In this fast-flowing water, there's no crocodiles...
..no elephants...
..there's just fish.
Lots of them.
For the people who have made the biggest wonders their home,
the rewards can be great,
even if their treasures are accessible only to the very bravest.
Between India and Bangladesh, there is another such wonder.
The Ganges river opens out into a vast delta, the biggest
on the planet, 2,500 kilometres wide where it meets the sea.
At its heart lies the vast forest of the Sundarbans...
its channels and islands, dominated by a single type of tree.
This is the largest mangrove forest on Earth.
And lurking within,
there's something terrorising the local people.
The men dared to venture into the Earth's most dangerous forest,
lured in by its riches.
These are the Mogli people of Bangladesh.
24-year-old Jelal Udin is leaving his young family
to make the most hazardous journey of his life.
His goal is to collect the Sundarbans' golden treasure, honey.
This will be Jelal's first time collecting honey.
His father will lead the expedition.
It's a terrifying journey, because every year in the Sundarbans,
up to 150 people are killed by a fearsome predator.
The Royal Bengal tiger.
HE GROWLS
Because of the risks, honey hunting is controlled,
restricted to just a fortnight every year.
So competition is fierce.
When the season officially opens,
it's a race to claim the best locations to find hives.
The men are entering a maze of mangroves with
thousands of channels, patrolled by 400 tigers -
the largest concentration on the planet.
THEY SHOUT
The men hope their shouts will keep tigers at bay.
Jelal is now entering the dark heart of the Sundarbans,
a vast wonder created by a single plant, the mangrove tree.
Their snorkel-like roots can draw oxygen directly from the air.
It means they can thrive in the tidal mud where other trees struggle.
And their flowers are pollinated by the very thing Jelal seeks,
the giant Asian honey bee.
But there is another animal which thrives here.
The fresh tiger prints are everywhere.
THEY SHOUT
The crew have risked their lives for nothing.
With fresh water running out,
they have one last day to find some honey.
But the Sundarbans is not the only vast natural wonder
shaped by a single plant.
From Eastern Europe to Mongolia,
the Eurasian steppe straddles almost a quarter of the globe.
The steppe only gets around 20 centimetres of rain a year,
not enough for most trees to survive.
Instead, it's a living wonder...
..of grass - the largest habitat on Earth.
For the nomads of Mongolia,
grass feeds the cattle on which they depend.
And the horses they use to herd them.
Bat Aden is a 16-year-old herder,
but he wants to be a horse breeder,
and the horse he's trying to catch could make that dream come true.
Because tomorrow, it will compete in the biggest
horse race in the province.
Last year, Bat Aden was a winning jockey in national races,
but he has a problem.
Mongolian racehorses are small and the rider's weight is crucial.
This year, Bat Aden is too heavy to race.
So he had to find another jockey to take his place.
Seven-year-old Sukhbat will ride for his cousin.
It's their last training session.
HORSE WHINNIES
HE LAUGHS
The race will be a big moment for Bat Aden's family.
Race day.
Today's event is being held to honour
the birthday of the steppe's most famous son.
Genghis Khan.
In charge of the race is the most powerful man in the province,
Governor Oidoff.
And for Bat Aden and Sukhbat, there's a new challenge.
The governor's eight-year-old son Nyambyar is a late entry.
The riders need to canter to the start line 5km away.
They will then turn and the race will begin.
THEY SHOUT
The more experienced riders have kept to the firmer ground
and made a good start.
But seven-year-old Sukhbat finds himself near the back.
HE SPEAKS HIS OWN LANGUAGE
The leading pack has gained a huge advantage
and the governor's son is among them.
Sukhbat begins to close the gap, passing more experienced riders.
SHOUTING AND CHEERING
But the leaders are already approaching the finish line.
The governor's son is pushing for victory.
But finishes second.
Just behind, Sukhbat is on the home stretch.
THEY CHEER
The pace has proved too much for other riders,
and some have fallen but are unhurt.
As the finish line approaches,
Sukhbat must resist a late charge by his closest rival.
He's pipped at the post.
Sukhbat's done well in his first race and finished in the top six.
Bat Aden's people and their horses
have been bound together on the great steppe for hundreds of years.
It's a partnership shaped and sustained by one type of life -
grass.
Back in the giant mangrove forest of the Sundarbans,
Jelal has one last day to find the honey
and avoid returning home empty handed.
They must move quickly.
In a channel this narrow,
there's a risk of being stranded by the outgoing tide.
THEY SHOUT
ALL SHOUT: Aaaaah!
Ah, la-la-AAAH!
Guarding the hive are thousands of giant Asian bees.
Their sting is many times more toxic than the common British bee.
If they swarm and attack, they'll kill.
The men hope smoke will make the bees docile.
This is Jelal's moment.
To be accepted as a full member of the crew, he must conquer his terror.
He leaves enough honeycomb for the bees to rebuild their hive.
The honey they've collected will earn Jelal 60...
..enough to make a big difference over the coming year.
The people, the bees and the mangroves
are bound together in an extraordinary relationship
in the Sundarbans,
a vast wonder of great bounty, but also great danger.
With the very biggest of Earth's wonders, even small changes
can sometimes transform the lives of those who live there.
Flowing through south America...
..the mighty Amazon river.
One fifth of all river water on the planet travels through it
and every year, this gargantuan wonder overflows
and bursts its banks, altering everything.
For two months, it means the great forests on either side
change from being dry land...
..to a magical water world...
...where fish swim through the trees.
A vast flooded forest, covering an area the size of Great Britain.
For the river people, this flooding brings with it something
that could change their lives.
An ancient leviathan the length of two men.
One of the world's largest species of fish.
The pirarucu.
When the Amazon floods, the pirarucu can enter the forest to feed.
Weighing up to 150 kilos,
it's very valuable for Amazon fishermen.
For Joao Edson, catching one will mean
he can afford to make ends meet.
To protect pirarucu numbers,
the Brazilian government allows only a short fishing season.
That window will close in just two days.
Joao and his neighbours work as a team.
They hunt pirarucu not with rod and line,
but the traditional way -
from trees, with harpoons.
The pirarucu is unusual, because it breathes air,
so the men know that at some point, the fish must surface.
They just don't know when.
He's missed.
And now the fish knows he's there.
Joao has failed to catch a single pirarucu this year.
With one day left of the season, it's a crisis for his family.
7:00am, and it's the fishermen's last chance.
They head back into the flooded forest.
Heavy rains this year have made the water especially murky.
Despite this, one of the men has finally harpooned a pirarucu,
but it's so strong, it's wrenched the harpoon from his hands
and swum to the bottom.
To lose it now would be a disaster but they can't find it.
They call Joao over. They desperately need HIS help.
Joao can do something extraordinary.
Years of experience mean he can locate the fish
with an unusual skill.
Joao can track pirarucu underwater by tasting where it is.
He's found it.
THEY SPEAK THEIR OWN LANGUAGE
THEY EXCLAIM
It's one of the biggest they've ever caught.
After it's gutted,
they sell the catch at market, a day's travel away.
The village split the money.
It'll keep them going until next year,
when the world's biggest river will again create its vast flooded jungle
and the fishermen can hunt this extraordinary fish once more.
Seen from space, the Amazon is a very obvious natural wonder,
but even when they are huge, not all wonders are so easy to spot.
The Raja Ampat archipelago in Indonesia is a paradise
of tropical islands,
but the true wonder here lies not on the surface...
..but hidden beneath.
The vast reefs here are the richest on Earth.
With over 1,000 types of fish,
and hundreds of types of coral, there are more species here than
Australia's Great Barrier Reef and the Bahamas put together.
And one creature rules this ocean kingdom.
The manta ray.
These giants with wingspans of up to four metres
gather here in some of the greatest numbers on Earth.
But they're endangered,
because the mantas are an easy and lucrative target...
..for poachers.
Mantas are slaughtered for Chinese medicines.
A kilo of gills sells for 400.
Manta numbers are in steep decline.
This is Ronald Makassar.
He's on his way to harpoon a manta.
But he's not a poacher.
He's a protector.
All year, he's been trying to harpoon a manta
with a radio tracking device, to help save the species.
More mantas are currently being slaughtered than born.
Ronald wants to tag a pregnant female
so the transmitter can reveal its birthing grounds.
It will help conservationists to protect the site from poachers.
But so far, Ronald's failed in his task.
And that's because of a hidden hazard that lies in the water below.
The currents of Raja Ampat are some of the strongest on Earth.
These super-strong currents are created
as water flows west from the Pacific into the Indian Ocean.
It's funnelled through Raja Ampat,
a narrow channel linking the two oceans.
Every day, the equivalent of 100 Amazon rivers squeezes
through this gap...
..bringing a constant flow of nutrients to feed the reef...
..and plankton to feed the manta.
But these currents make Ronald's task very difficult.
Ronald spots a female.
He can tell her sex because of the two flat fins
at the base of her tail, and a faint bulge reveals she's pregnant.
He's got just one shot.
Windy season is just days away and its rough waters mean
Ronald won't be able to tag for another year.
With just a few days left,
Ronald knows he'll need to try a different approach
if he's ever going to help secure a future for the mantas.
Not all nature's biggest wonders are found
in such remote corners of the planet.
In France, where the Rhone river meets the Mediterranean,
there's one of Europe's largest and most secluded natural wonders.
The Camargue.
1,000 square kilometres of pristine salt marsh,
it has preserved a lost world.
Flamingos in western Europe.
Pure white horses.
And black bulls.
And this wonder has shaped the culture of the people here too.
In one dangerous way.
The Course Camarguaise is a contest between man and bull.
Unarmed bull runners - raseteurs -
try to outwit bulls with their agility...
..snatching tokens from between their horns.
The bulls are not harmed,
but for the raseteurs, it is a potentially deadly game.
CHEERING
But before any contest, cowboys riding the Carmargue's white horses
have to round up the bulls in the salt marsh.
Across the rest of Europe,
while every great mammal has been hunted to extinction,
here, the secluded Camargue has offered feral bulls safe haven.
They have remained almost unchanged here since the last ice age.
The cowboys choose a bull with the right fighting spirit.
HE SPEAKS FRENCH
They name him after the Roman god of fire - Vulcan.
Later today, Vulcan will take on the raseteurs in his first-ever contest.
Vulcan won't be the only novice in the arena.
Vincent Felix is 19.
If he does well today, it could launch his career as a professional raseteur.
Until now, Vincent has trained with bulls wearing blunted horn protectors.
Vincent's father was a champion raseteur. He's come to watch.
To win, Vincent needs to score more points than a dozen other raseteurs
and face several different bulls.
BULL BELLOWS
Vincent fails to score in the first two rounds...
..but gets his first points in round three.
But he still trails the leaders.
Now there's just two bulls left.
First, Blackhorn.
Half a tonne of brutal fury.
But Blackhorn keeps escaping the arena.
No-one can add to their points.
Vincent is still behind as Blackhorn is taken off.
Now the last bull.
Vulcan.
BULL BELLOWS
Vulcan is seeing off the raseteurs with frightening ease.
For Vincent, his last chance is slipping away.
He's taken the highest scoring token from Vulcan.
CHEERING
Thanks to Vulcan, Vincent's career as a professional has begun with a victory.
Man and bull brought together in ancient contest,
at the heart of one of Europe's largest natural wonders.
The Camargue.
Back in Raja Ampat, a break in the weather has given Ronald
a final chance to radio tag a pregnant manta.
With the strong currents wrecking his chances,
Ronald's gambling on a new approach.
He chooses an area where the currents are weak,
but there's no guarantee of mantas,
So he must hope that the mantas come to him.
But he has only 45 minutes of air.
With just five minutes left, his luck turns.
And one of the mantas is a pregnant female.
He must get above her to strike.
Now is his only chance.
Perfect hit.
Woo! Woo!
Ronald has taken a crucial step in the battle to save the mantas
who depend upon this vast wonder of the oceans -
the magical reefs of Raja Ampat.
Our Earth's natural wonders are places of danger...
..reward...
..and great beauty.
These unique places
have created unique challenges for their inhabitants.
And they have fundamentally shaped the lives of the people
who dare to call them...home.
One of the biggest tests the Earth's Natural Wonders team faced
was how to follow local fishermen
as they made perhaps the most dangerous fishing trip in Africa...
..and film them at the very edge of Victoria Falls.
But the first difficulty is how to safely film
the fishermen as they cross crocodile-infested channels.
There's a sort of upper time limit to how long you can
linger in the water when there's crocodiles around,
because basically they kind of clock that you're there and then you become a potential target.
Things quickly get trickier.
Three elephants turned up as well,
so now we've got Mick who's checking for crocodiles and we've got
Tom who's meanwhile checking for elephants at our back here.
Hidden by the bush,
the elephants need to be bypassed by both fishermen and crew.
ELEPHANT BELLOWS
Well, we're having to move because we're in the route
that the elephants are likely to want to take.
The fishermen's final destination is a secluded outcrop
at the very edge of Victoria Falls.
The film crew need to transport the heavy camera equipment by boat.
ENGINE CUTS OUT
But only 200 metres from the edge, the engine fails.
This close to the falls, the current could drag them over the lip.
Instead, by steering the drifting boat, they reach the shore.
None of us really know how we're now going to get to film
the edge of the falls, because the one boat that we've got
that will allow us to do that, the engine's screwed, basically.
It's a bit of a problem.
The crew managed to change the engine
and get closer than ever to the edge of the falls.
The new engine isn't up to much, either.
Third time lucky.
This is what we would call the point of no return.
No boats go past this point.
Any further and the boat would be swept off the edge.
OK, home sweet home.
Now the crew must unload.
They have just enough time to set up the jib crane for the final shots.
So we've got the jib set up
right next to the edge of the falls,
but in the last hour, the wind has changed direction
and now there's this almighty spray
covering all these rocks, making it really, really treacherous,
so I'm extremely glad I put a safety rope system up for the guys
operating the jib, because it's absolutely lethal at the edge now.
But in the last hour of good light, the mist clears
and the team finally manage to film the fishermen at the very edge
of one of Earth's greatest natural wonders.