Of all the wonderful places in the world, one continent holds
more riches than any other.
It covers almost a third of the land on Earth.
In the south, stand vast forests.
And to the north...
..lies an immense frozen wilderness.
Much of the centre is dominated by deserts.
And at its heart are the world's highest mountains.
Off the coast of this continent,
stretch the richest seas on Earth.
And that's not all.
This is the most populous place on the planet.
Here, animals live alongside humans in the most remarkable ways.
If you think you've seen the best the natural world has to offer,
think again.
There's nowhere else on Earth with so many untold stories.
Welcome then, to Asia.
Asia is the largest continent on Earth.
With a coastline over 100,000 miles long,
it's surrounded by three oceans and 21 seas.
Its waters stretch from Arabia, through the Indian Ocean
and Southeast Asia, to the edge of the Pacific.
Connected by some of the world's most powerful currents...
..these seas are the richest on the planet.
And the animals in Asia's oceans are as spectacular as they are diverse.
In the warm waters of the Western Pacific,
lives a dramatic little fish, with pouting lips and dazzling stripes...
..the flamboyant Moorish idol.
This one is looking for a partner.
Moorish idols normally breed in pairs.
But here, they do something that no others of their species do.
They congregate in huge numbers...
..before swimming away from the reef, to spawn.
But so many fish attract attention.
A grey reef shark...
..and it's not alone.
With so many hiding places, there is safety on the reef...
..but they must get out past the sharks.
Finally, they make a break for it.
Now in open water, they can swim into the blue.
But they've been spotted.
A few sharks can be avoided...
..but hundreds are a different matter.
To have any chance of survival, they must stay in a tight group.
The sharks try to split them up...
..and pick them off.
After two hours of chasing,
only the strongest are left.
The few survivors swim in tight spirals, desperate to avoid capture.
The sharks, tired and full,
one-by-one, abandon the chase...
..until only the luckiest and fittest Moorish idols survive.
No-one knows exactly where they spawn.
But the developing young are carried away to safety by the currents.
From the Western Pacific, comes one of the most powerful
currents in the world - the Indonesian Throughflow.
It sweeps between Borneo and Sulawesi, and into
the Flores Sea, where it hits Indonesia's Lesser Sunda Islands.
Here, water is forced between the islands at a rate
of 15 billion litres a second.
And this produces some of the world's most intense currents...
..and whirlpools.
Off the island of Komodo,
the water is funnelled into fast-flowing torrents,
which concentrate the plankton it carries...
..providing food...
..for giants.
Manta rays.
With a wingspan of up to five metres,
these mantas exploit the powerful currents.
They feed by filtering plankton from the water.
Such a feast makes this an excellent place to produce young.
When the adults need a break, they head off for a bit of pampering.
Out of the main flow are cleaning stations,
staffed by hundreds of butterfly fish.
The cleaners remove parasites and dead skin,
and get a meal in exchange for their services.
And the mantas get a welcome break from the ripping currents.
Refreshed, they can go back to feeding.
As the Indonesian Throughflow continues, one branch flows
past Bali, to Java and some of the richest
coastal forests on Earth...
..mangroves.
These are places where nothing is as you might expect.
Trees grow in the sea...
..and fish live on land.
A dusky-gilled mudskipper...
..only five centimetres long,
but a master of these swamps.
As long as they can stay wet, they can absorb oxygen from the air,
and they spend most of their life out of water.
Joints in their pectoral fins enable them to walk...
..and they can leap with a flick of their tail.
This one is seeking a mate with whom to start a family.
But first, he needs to dig a breeding burrow.
Mudskippers will shift up to 300 times their body weight in mud,
one mouthful at a time.
Tiring work!
With the dirty job done,
it's time to find a female.
But the mangroves are full of obstacles.
A special set of grasping belly fins, however,
enable skippers to become climbers.
And when there is a dead end...
..a mudskipper simply skips across the water's surface,
a metre at a time.
What's this?
An open arena...
..full of females.
Excellent!
But there are also other males here looking for partners.
To win a female, they must duel.
But no-one is backing down.
Victory and the opponent beats a hasty retreat.
And it looks like this male...
..has caught someone's eye.
A quick wave should seal the deal.
It's a date.
They head back to his place...
..ready to start a family of their own.
Mangrove forests are essential for the survival of Asia's mudskippers.
And trap four times more carbon than forests growing on dry land.
Today, Southeast Asia holds a third of what is left of these
precious forests...
..adding clean, fresh water to the Indonesian Throughflow,
as it travels.
Sweeping away from Indonesia,
the current heads west across the vast Indian Ocean...
..carrying with it a whole host of drifters.
And some objects provide entertainment
for one of Asia's giants.
A baby sperm whale plays with a mangrove seed,
so practising his coordination.
He produces pulses of high frequency sound from his large head,
sonar that will eventually enable him to locate prey
in the black depths...
..and zeroing in on a tiny seed is great practice for doing so.
When you're as big as this,
grabbing something the size of a pencil is not easy.
With play over, it's time to get back to the family.
The grown-ups are taking a nap.
It's thought that the reason they sleep upright is to make it
easy to bob up for air.
The calf is keen to join in.
But it's not as easy as it looks.
Staying vertical takes practice.
And when you get the hang of that,
the next challenge is buoyancy.
Holding just the right amount of breath is an art.
Too little and you sink.
The adults tenderly correct his mistakes.
He still has a lot to learn.
In his 70-year lifespan,
he will explore much of the Indian Ocean.
From here, the Indonesian Throughflow continues west...
..but a very different kind of traffic is moving northwards.
Shipping.
Major international cargo-lanes run from the Indian Ocean
into the Red Sea, which divides Asia from Africa.
At its Northern end is the Suez Canal.
One third of the world's container freight travels along it
and emerges into the Mediterranean...
..one of the planet's most polluted seas.
Here, on Asia's westernmost coastline,
this Israeli power station discharges water ten degrees hotter
than the surrounding sea.
Astonishingly, this has become a refuge for one of the most
vulnerable of species...
..dusky sharks.
Mediterranean sharks are the most endangered on Earth.
But up to 100 females come here in winter...
..and each one of them is pregnant.
It's thought the warmth speeds up
the development of their unborn young.
This power station has created a shark sanctuary by accident.
But elsewhere in Asia,
deliberate steps are being taken to protect marine life.
Over 5,000 miles away on the other side of the continent...
..life is booming in the unlikeliest of places...
..the tiny island of Tyuleniy, in far-eastern Russia...
..a disused hunting settlement.
Here, enormous numbers of fur seals were once killed
annually for their skins.
But hunting restrictions have produced a spectacular recovery.
Over 100,000 Northern fur seals now come here each summer.
It's one of the largest colonies in the world.
The beaches are jam-packed.
BLEATS LOUDLY
Huge, territorial males compete for space.
It's dangerous for the tiny pups,
which weigh just a 50th of the adult bulls.
The aggressive males are only focused on the next challenge.
When fights break out, the pups are ignored.
In the aftermath, many pups lie injured.
Life on the beach is full of danger...
..but it's no safer in the sea.
Orca.
Fur seals returning from fishing must run the gauntlet.
But these orca are specialists...
..ramming and tail-slapping to stun their prey.
And when their victim has been disabled...
..they drown it.
Many pups are left as orphans...
..but enough will survive to support this now healthy
population of Northern fur seals.
This richness in Asia's shallow seas can also be
found in some of its deepest waters.
Every night, billions of creatures travel up from the abyss.
It's the largest regular movement of life on the planet.
Strange life-forms come up to feed in the surface waters...
..among them jelly-like salps, which have tiny crustaceans
living inside their bodies.
As dawn arrives, they return to the safety of the deep.
But some creatures, gathering in the Sea of Japan, are about
to embark on a one-way trip out of the depths, never to return.
Firefly squid.
They live for just 12 months.
It's thought that they use their blue bio-luminescent lights
to confuse predators...
..and their green lights to communicate with one another.
No other deep-sea animal can see green.
It's the squids' own secret code.
Some quarter of a billion females are heading to the surface.
In the shallows, they lay thousands of eggs in strings...
..the final act of their short lives.
With this done, their bodies are programmed to die.
Here, on the north coast of Japan,
they wash up on the beaches of Toyama Bay.
Their lights fade, as life drifts away.
Their eggs, however...
..are beginning to hatch.
Sinking into the vast darkness of the deep sea,
they won't return to shallow water for a year,
when it will be their turn to lay eggs and then die.
2,000 miles south, in the western Pacific, lie wide
expanses of shallow seas around the Philippines,
Malaysia and Indonesia...
..the so-called Coral Triangle.
Here, there are more abundant coral reefs than anywhere else.
It's the richest concentration of marine life on the planet.
Three-quarters of the world's coral species are found here...
..and over 3,000 species of fish.
It's every bit as diverse as the Amazon rainforest.
Coral reefs truly are the ocean's bustling cities.
Many residents have evolved ingenious ways of solving
the problems of living in such close quarters.
But some appear to be completely defenceless.
Meet the sea bunny.
Just a few centimetres long,
this tiny sea slug has no shell for protection...
..no eyes to spot danger...
..and travels at a snail's pace.
It's looking for food.
What appear to be its ears are, in fact, finely-tuned chemical sensors,
that enable it to "smell" its way to its next meal.
But on the reef, predators are everywhere.
When you can't see...
..it can be hard to avoid trouble.
Alien-like beasts patrol the nooks and crannies of the reef.
This one filters its food from the water...
..and is no threat to the sea bunny.
But not everything here is quite so harmless.
The Moray eel, powerful and fast...
..but apparently not keen on slug for dinner.
A scorpionfish, one of the reef's most deadly inhabitants.
Extravagantly camouflaged, it waits for prey to come close...
..then swallows them whole.
But the sea bunny just walks all over him.
And now, it's headed straight for a deadly-poisonous blue sponge.
Blind and hungry, it's about to take a bite.
It seems that its luck has finally run out.
But, no, this is actually its favourite food.
It's immune to the poison...
..and by eating the sponge,
the sea bunny has made itself toxic to predators.
No wonder it's untouchable.
As long as it can maintain its blue sponge diet,
the sea bunny will be protected against the dangers of the reef.
With so many complex survival strategies...
..life for predators on the coral triangle
can require complex tactics.
This snake, a black-banded sea krait,
has venom ten times stronger than a cobra...
..a forked tongue that enables it to sniff out prey underwater...
..and a flexible body,
so it can squeeze into crevices on the reef to look for prey.
A formidable killer, it would seem.
Yet, hunting fast prey is not one of its abilities.
It's slow with poor eyesight, hardly the deadliest of assassins.
If only it were fast and agile...
..like these bluefin trevally.
They rely on sheer speed to catch their prey.
Unlike the snake,
they are too big to get between the arms of the coral.
But these two struggling species have found a solution.
They work as a team.
The trevally leads...
..indicating places where prey could be hiding...
..which the snake then investigates.
As they roam the reef, they're joined by more trevally...
..and more snakes.
Soon, they are an army.
The trevally find a target.
The snakes head in...
..and the trevally cover the escape routes.
There's nowhere left to hide.
The trevally catch the fish that are flushed out...
..and the snake eats anything left inside.
Each species benefits from the partnership.
The hunts are so successful that they attract
hundreds of trevally and snakes.
This behaviour is extremely rare,
and has only been seen in Asia's coral triangle.
Innovation and teamwork are critical to success
in these competitive waters.
These relationships and strategies developed over millennia,
are a consequence of the extraordinary richness of
Asia's seas.
And whilst our influence is now not far away,
Asia's oceans still remain a world of wonder,
offering spectacles not found anywhere else on Earth.
The Asia team explored many of the continent's 21 seas.
They spent thousands of hours underwater,
filming the spectacular diversity of life.
But their biggest challenge was getting up close with
some of the most powerful currents on earth.
The Indonesian Throughflow carries ten times more water than all
the world's rivers combined.
The tide has to make its way from the Pacific to the Indian,
and that's a huge amount of water.
And as it does that,
it gets squeezed through these islands, which
creates intense currents, but also brings an incredible amount of life.
The team want to capture this immense power up close...
..but the fast currents are making filming difficult.
For their first attempt, they use a pole-mounted camera.
But getting the boat into position is almost impossible.
We're fighting a losing battle. Yeah. We'll drop it.
Let's go back to the main boat.
David thinks he has a solution, but it's radical.
He's going to get in the water himself,
using a floating camera rig to film inside the vortex.
We'll see the swirling water, literally the opening of the
funnel of the whirlpool, that's what I want, it's like the epic shot.
If the shot works, it's going to be amazing.
It's going to really tell the story of the currents nicely.
So, I think what we have to do is put David up current, initially,
but close-ish in to the island,
to get those swirls, as you come past.
What's the normal advice for divers here?
Normally, we'll actually jump right next to the island where there's no current.
They stay out of the current entirely... Yes.
..which is the opposite to what you're going to be doing! Yes. OK, yeah.
This challenge is unlike anything David has faced
in 30 years of film-making.
I'm going to add two life jackets to the camera rig, and you know
if I start to get sucked down I'm going to just hang on to that.
The key to staying safe will be buoyancy.
Yeah, I don't know if I can get this third one on.
Three life jackets should resist the pull of the whirlpools.
It's not that bad.
What do you think? Money? Yeah.
The team decide to dive on the rising tide
when the currents are weaker.
I think I'm plenty floaty!
David's home-made protection is holding up well.
The current is running fast, but the whirlpools aren't forming.
David, nothing? Nothing.
Nothing at all? Like, I... I feel the current, and I, like, I don't
see any, like, whirlpools, bubbles, hardly anything in the water.
Do you want picking up?
Yeah.
It seems that if David is to get his shots...
..he will have to brave the much faster falling tide.
Preparation will be key to success.
Whirlpools only last a few seconds,
so to get in the right position, the team needs eyes in the sky.
Drone's in the air.
OK, copy, copy. What do you guys see?
The current looks strong on that eastern edge of the island.
If you can spot good places where the whirlpools are cropping up...
Mark, Mark, the swirl's forming on the edge you're at.
Right, thanks, mate.
Look, we've got some, definitely some forming here.
David must get to the whirlpools before they dissipate.
Is this a good spot? Yeah, I call it right here.
OK, clear to go.
You're going to get sucked in pretty quickly.
Behind you, David.
Mark is ready with a throw rope, in case of trouble.
You OK?
Do you want the rope?
He's OK.
He wants to carry on.
David's commitment is paying off.
He's starting to get the shots.
But the whirlpools are growing stronger.
That is putting him right in the whirlpool zone.
He's getting sucked in.
All he can do now is hang on.
OK, can we get closer to David?
Whoa!
At last, the whirlpool spits him out.
David, you OK?
Yeah.
It's hairy. It's not doing anything for my nerves, let alone David's.
It's time to get back into the safety of the boat.
OK? Yeah.
It had me. Like, I could feel myself going bloob, bloob, bloob, blub, blub.
Really? Like that, but I had, I had enough, I kind of kept my hands on the camera.
Yeah. I didn't even see it coming, suddenly I was like... Yeah, yeah, yeah.
A good whirlpool, huh?
David's plan has succeeded.
Yeah! He's faced Asia's ripping whirlpools,
and captured their fierce beauty, as never before.
Next time, we journey to Asia's remarkable mountains...
..a world full of surprises...
..and home to some of the most captivating creatures on the planet.