Original subtitles

No one, and I mean no one, has ever been near the bottom of this trench.

We don't know what's down there. I've never seen anything like that.

The sea temperature is extremely warm.

One of the first symptoms of heat stroke is people acting irrationally. Hey, I'm

going as fast as I can.

You can't make it.

Nothing on the sun.

Humankind has explored every continent on Earth.

We've climbed its tallest mountain.

And even journeyed into space.

Thank you, Mr. President.

But there's a vast swath of our own planet that has remained a mystery.

The deep ocean.

Stretching down over 35 ,000 feet into crushing pressures.

it's been near impossible to reach.

Until now.

New engineering breakthroughs are driving an audacious global mission to

the deepest points of all the five oceans for the first time in history.

These pioneers will push technology to the limit. To open

up this final frontier as never before.

Trying to, like, mentally put yourself at the bottom is just mind -blowing.

Mapping hidden landscapes.

Discovering unknown life forms.

What the F is that?

And unlocking the secrets of how life in the extreme deep ocean affects our

entire planet.

Millionaire explorer Victor Vescovo has spent the last four years preparing and

planning to make exploration history.

I've been doing some somewhat risky things all my life.

Coming up with a mission that's never been done before, that's extremely

exciting, that's difficult, and seeing it through to its conclusion.

Victor has set himself the goal of being the first person to head to all five of

the Earth's oceans, find their deepest points, and explore their hidden

So far, he has completed two of the five.

Overcoming storms in the Atlantic to find new species.

At bottom.

And braving freezing waters to triumph in the Southern Ocean.

Great job.

All right, picture.

Their third deep dive is in the Indian Ocean.

This is the youngest of the oceans.

It's also the warmest, with an average surface temperature of 90 degrees

Fahrenheit.

Beneath the waves, the sea floor is one of the most geologically volatile areas

in the world.

A landscape of unpredictable falls, fractures, and earthquakes that over the

last few decades have generated five of history's deadliest tsunamis.

The ocean's deepest point lies at the epicenter of a tsunami trigger zone, the

Java Trench, where two giant flakes in the Earth's crust collide.

A crucial part of Victor's mission will be to search for evidence on the

seafloor of what is causing the tsunami.

The more data we have from the deep oceans, the better our models could be

predict these things.

No one, and I mean no one, has ever been near the bottom of this trench or even

explored it.

We don't know what's down there.

At over 23 ,000 feet deep, the pressure will be immense.

Any ordinary sub would simply implode.

So Victor has commissioned a pioneering new design.

Go ahead and jack it up.

Roger. Its secret strength lies at its core.

The cockpit is a ball of three and a half inch thick titanium.

If this wasn't a perfect sphere, it could crumple like a tin can.

Inside, a rack of oxygen tanks provides up to 96 hours of emergency life

support.

If someone needs to go down to the bottom of the ocean, the submarine's it.

It's now the deepest diving submersible in the world. In fact, it's actually the

deepest diving vehicle, period.

You know, I think the submersible is the most significant vehicle since Apollo

11. This is a vehicle that will allow us to explore the last frontier on Earth.

But if something serious goes wrong at full ocean depth, there's no hope of

rescue. It's the only thing in the world right now that can go below 7 ,000

meters. Not even a remotely piloted vehicle can do that.

We're getting the tow line off first.

And the sub is still very much a prototype.

There you go.

In the first two ocean dives, the sub team faced a massive learning curve.

There's a reason why nobody's done this before. It's not easy.

It's going to an extreme, extreme environment. There is no rescue plan.

This has to come back. It has to work.

Sort of testing by breaking.

Black on the tag light.

Why are we doing it?

And there's always a lot of heartache in that process because for every two

steps you take forward, you've got to come back and relearn one of them.

What am I supposed to do?

It can take up to 30 or even 40 dives with a brand new submersible,

especially one designed with these extreme features.

to get it to where things are working well.

Okay, you guys ready?

Roger, go ahead.

Even if the sub is fully operational, the team face a major hazard of the

Ocean.

It's tropical cyclone season.

The sea temperature here at the moment is about 30, 31 degrees Celsius, which

extremely warm, and warm water is the fuel of cyclones.

The pressure is on to complete the mission before a cyclone forces them to

shelter.

First, the team need to use their high -resolution sonar scanner to map the

uncharted depths of the Java Trim and pinpoint the precise location of the

deepest point of the Indian Ocean.

It's one of the most advanced sonars in the world. It's actually kind of

military -grade, and it has the capability to...

acoustically survey the bottom of the ocean all the way to full ocean depth

map it.

The early scans are already revealing crucial new evidence to help a key

of this expedition.

The search for the causes of the deadly Indian Ocean tsunami.

In that northern wall, we found at least 14 slope failures.

Some of those are four or five kilometers wide, where big, big chunks

essentially just...

come loose during earthquakes and just slump to the seafloor and they can be

responsible for tsunamis.

Monster landslides like these displace vast amounts of water that on the

turn into devastating tsunamis.

The scans have also revealed a near vertical cliff that may be the site of

next catastrophic collapse.

What we need to do is actually go down and get some eyes on that and try and

find out whether these areas are...

about the fall, or if we've got areas that fell a long time ago and the whole

area is actually quite stable.

The team decide to add to their mission a research dive down to this cliff.

The phonar has identified a key geological feature which otherwise would

have been found, and you have the tool to go and dive on it.

Now this is great.

This is what we're here for, to find things like this.

It's a one -off opportunity to explore the dark secrets of the Indian Ocean,

it will be the first time the sub has had to navigate so close to a

hazardous rock face.

It's kind of hard to get a sense of angle when you're down there because

field of view is only about 10 or 15 meters.

Victor decides to put at the sub's helm the most experienced sub pilot on board

and the builder of the sub itself, Patrick Lahey.

Okay, so you go down, and you'll try and find the wall first.

You know, we should have a plan and stick to that plan.

Just get a lovely, beautiful video of that slope.

Chief Scientist Alan Jamison will join Patrick to guide the search.

All right, see you guys.

Hat, shirt.

Okay, LF, summer's clear. You're clear to dive.

Roger that, Kelvin. I got a green board.

Two and a half hours after leaving the surface and over 22 ,000 feet down,

finally, their target comes into view.

Oh, there's the wall.

We're just going to take it easy here now.

The cliff towers over 600 feet above them.

Patrick will need to be extremely careful.

A sudden rockfall could put the sub in serious danger.

And down here, there's no other submersible in the world that can come

rescue.

Wow, it's deep.

I have to give it a little bit vertical up there, buddy.

Oh, there's a... Excuse me, look at that.

Big boulders on my right there.

Oh, oh, oh, oh.

Really, my fault.

This is a massive other hand.

Scientists Alan and sub -builder Patrick are diving into an active geological

fault line where no one has been before.

I'm backing away, man.

They are seizing a unique opportunity to investigate the origins of deadly

Indian Ocean tsunamis triggered by massive underwater landslides.

Could this precarious wall be the next disaster waiting to happen?

Those are big chunks of, looks like volcanic rock, right?

Yeah.

We see these black rocks and these are rocks that were once molten and they've

cooled down and...

They're black because they've cooled down really quickly, so they've been

erupted onto the sea floor.

I'll just creep up the wall here. It's going to bring us in closer.

So look how precarious this rock is.

This is a great big tower, this.

As you can see from that, it's not going to take much of a rumble for that to

collapse.

A landslide here, and the sub could be buried under a cascade of rocks and

sediment.

Whoa, what the hell was that?

Could you send me a data update?

LF, could you repeat your last?

I'm backing up.

Look at the colours of the rock.

Stunning.

Something that I wasn't expecting are these multicoloured areas of what look

be bacterial mats.

Bright white, oranges, there's even some blues in there. Really spectacular

colours. These are bacteria living off the fluid that is coming out of the

seafloor. It is an extraordinary form of life, feeding on the seabed itself.

And it's the first time anyone has seen it at such enormous depths in the Indian

Ocean. Yeah, it's starting to flatten out.

The mission has given the expedition a remarkable insight into one of the most

volatile geological hotspots in the world.

Actually getting eyes on the seabed and looking at some of these mass movements

and the block failures, we can start to piece together with a bit more certainty

the different...

processes going on in the java trends some of these are related to potential

tsunamis in the future or indeed in the past it's on our job right we found the

wall surface lf present depth at the top of the wall yes

excellent so happy for him

surface lf uh requesting permission to leave bottom

Roger that.

Releasing surfing weight now. There we go.

Despite a few scratches to the sub's outer housing, the dive has been a huge

success.

But as well as studying the geology of the trench, Chief scientist Alan

is also eager to explore, for the very first time, what life forms have adapted

to live in its crushing depths.

The Indian Ocean is kind of renowned for having never really been properly

studied, and that's the same for the shallow water, never mind the very, very

deep water.

A set of underwater probes known as landers, packed with technology, will

baited cameras to film life on the seabed.

The target is in an area near the bottom of the Java Trench.

But first, the probes must pass through ever -deeper layers of the Indian Ocean,

where remarkable creatures find their home.

From the sunlight zone, where sunfish the size of pickup trucks bask on the

surface.

And dugong, distant relations of the elephant, graze on sea grass.

To the Twilight Zone, where monstrous six -gill sharks, unchanged from the

of the dinosaurs, lurk during the day, surfacing to hunt by night.

And where leatherback turtles, the deepest diving reptiles on the planet,

hunting for jellyfish.

Their flexible shells and collapsible lungs make them perfectly adapted to

survive the crushing pressures.

Deeper still, into the midnight zone, where vampire squid use their cape -like

foal, lined with tiny spines, to protect themselves against attack by deep

-diving predatory fish.

And slender snipe eels use microscopic hooked teeth on their beak -like jaws to

snare shrimp.

Finally, the scientific probes reach the very deepest zone of the Indian Ocean.

The Hadal Zone.

Now their cameras are the very first in history to film in this inhospitable

landscape. And they capture rare footage of an elusive deep ocean hunter.

Nobody really knows anything about them. Their common name is Assfish. Not a

great name. Not a great name.

If you look at it, it's got its double nostril here.

So it's got massive nostrils. So it doesn't care about the bait. What it

is where it can smell bait, there's going to be an accumulation of

So it just turns up and just picks them up.

Once the crowd of the shrimp -like scavengers arrive, it's dinner time.

Then, from one of the darkest, most remote parts of the planet, comes the

of creatures, a Dumbo octopus.

Remarkably, it's the deepest octopus ever filmed, by almost 6 ,000 feet.

Its tentacles are joined together by a web of skin to form an umbrella -like

body, and the huge ear -like fins that give the Dumbo its name help to make it

an extremely agile swimmer.

It's waiting for the bait to lure its favorite meal.

An unsuspecting deep -sea crustacean is moving across the seabed.

In such a pitch -black home, the Dumbo's eyes are virtually sightless.

Instead, it uses sensors in its tentacles to pinpoint its prey.

Quite often what octopus do is they'll sit on top of a crustacean and they'll

bore a hole through the back of its shell and they'll inject it with saliva

it dissolves the...

The shrimp, for example, from the inside, then it sucks out.

That's disgusting.

The probes have brought back remarkable images from the deep.

And now the scanning team have dramatic news for the expedition of Victor's

ultimate target.

This tiny sinkhole is the deepest point in the Indian Ocean.

It will be the most challenging of the deep yet attempted.

We're going to drop right into it, almost like trying to drop a marble into

bucket 50 meters down.

My highest priority is getting you safely back on board.

The scanning team have finished mapping the previously uncharted reaches of the

Java Trench.

It is a critical moment in the mission, because the trench might not hold the

deepest point in the Indian Ocean after all.

The team now need to compare the data with a rival candidate scanned on their

way, a fracture zone off the coast of Australia called Diamantina.

This yellow dot right here is the deepest point within this big basin of

Diamantina fracture zone at 7 ,019 meters.

If the Java Trench turns out to be shallower, then the expedition is 1 ,000

miles off course.

We continue to learn new things.

I think Kathy and her team understated what they've done, but we have solved

mystery that has always been around, which is what is the deepest point in

Indian Ocean?

Until this week, no one could definitively answer that question. In

was a big debate whether it was the Diamantina or the Java Trench.

Well, it is the Java Trench. It's not just the Java Trench. It's in a place no

one thought it was.

It's in the center of it, not the east or the west.

But to reach this deepest point will be a massive navigational challenge.

In the middle of the Java Trench is this tiny sinkhole that we actually have

determined to be the deepest point in the Indian Ocean.

And Victor is diving that.

We're going to drop right into it, almost like trying to drop a marble into

bucket 50 meters down.

This one you could actually miss.

If the team get their calculations wrong, Victor will be navigating a

dangerously rocky landscape with the risk of a damaging collision.

Coming up, EC. To help Victor find his way.

the team drop one of their robotic probes directly above the deepest point.

It has an onboard modem to communicate with the ship and the sub.

Victor will then have to find the probe to reach the deepest point.

Normally, two other probes are also launched to other sites on the seabed to

help calculate Victor's exact position.

On this dive, the team are gambling that Victor can navigate alone.

We don't have a vast open plane down there.

We thought we would put the lander directly over top of the target, but you

directly on the target. Without the three landers to triangulate, we won't

able to guide him to the actual position, so it is a little bit riskier.

If he sees the lander, then he's at the deepest point.

With the probe now signaling from the seabed, the team need to launch Victor

quickly as they can.

The tropical cyclone seen brewing on the horizon is now gathering strength and

threatening to end the multi -million dollar expedition before Victor has had

chance to complete his dive.

So it's a large storm system.

It's about 300 miles across.

It's generating this huge vortex with cyclone running at about 65 knots, maybe

75 knots, and waves of 6 to 8 meters.

And we are just up in this area.

There's an element of chance in all of this because it depends on where the

cyclone is drawing its fuel from as to where it'll head. We can't dally too

here. It could make life a little bit difficult for us. Here in the tropics,

can usually find somewhere to hide, but of course they'll rob us of any chance

to do a dive.

The nightmare scenario for me is the weather picks up very quickly, very

and then we have trouble recovering it.

If Victor is going to become the first person to touch down at the deepest

in the Indian Ocean, the team need to get him launched as quickly as possible.

Okay,

Victor, ready for you.

Guys, grab that. Grab that.

Report is on and good. I have a green board. I am due to launch.

Roger.

Swimmer is clear. You are clear to dive.

Swimmer is clear. Enabling thrusters.

And he's gone.

You've died.

All right, we are descending.

Seems a little slower than it did in Southern Ocean, 15 meters per minute.

That's pretty slow.

It could take a while to get down.

Present depth, 849 meters.

Well, that's awfully slow, isn't it?

It's 0 .7.

So 0 .7 meters a second is 42 meters.

A minute.

He went 400 meters in 15 minutes. That does seem slow.

Oh, wow.

Roger, 1077.

He's going real slow.

Something's not right.

With a mission -critical cyclone building over the horizon, Victor's

be the first person in history to visit the deepest point of the Indian Ocean is

in serious danger of unraveling.

He's going real slow.

Something's wrong.

The sub is dragged down through the water by a set of steel weights held in

place by two electromagnets.

The weights need to be heavy enough to override the specialist buoyant foam

block that will ultimately pull the sub back to the surface.

I can only assume that something's dropped off.

It's the only thing it can be. I suspect that one of the magnets has failed.

Which was the one that had a little bit of corrosion on it? It was the aft one.

I cleaned that all up this morning.

So, you know, we're just burning daylight.

Patrick,

as Mission Control Chief, now has a difficult call to make.

To risk a lengthy dive, or pull the plug, get the sub back on the surface

hope there's time for a second attempt before the cyclone hits.

Roger that.

Victor, I'm recommending an abort.

I do not believe you can reach the bottom.

I understand you suggest abort.

Pretty disappointed.

You're all good.

Okay, do be advised that he's been given clearance to surface. ETA is just a

couple of minutes.

Great, helping.

Roger that.

Let's roll.

Hey. Hello. Hey, how you doing?

Good feedback. Yeah, good feedback.

The pressure is on to get the sub fixed quick and make a second dive.

I got some little fetter spikes.

It's a complex system.

There are many, many elements, whether it's the ballast system or whether it's

the communication system.

Okay, you guys ready?

I don't know what's going on here.

There's so many things that have to work just right for this ballet to come off

without a hitch.

But in boiling temperatures pushing 84 degrees Fahrenheit, the sub -engineering

team are nearing breaking point.

Okay, I'm going as fast as I can.

There is a lot of stress on people to get everything right.

Oh, Frank, turn it off.

Had enough, man. Ready to go home.

Hang on a second.

You got a hose trapped in there.

I think people are learning, you know, kind of what they have to do and how

attention to detail they have to have to make it all work right.

While the engineering crew work overnight to fix the sub, the scanning

found stunning new data in the trench, revealing a second explanation for the

devastating Indian Ocean tsunamis.

So that's from there, right? Yeah, I think it's a faulted seamount.

A series of massive hills on the trench floor.

Extinct volcanoes known as seamounts that act like ticking time bombs.

We've identified a number of seamounts that are in the process of being

in the trench axis of the Java Trench. The trench lies along a volatile seam in

the Earth's crust where two giant plates collide.

Monumental forces are grinding one plate down under the other, and the seamounts

are in the way.

But that area there doesn't look like that created by the seamount being

subducted under the plate. You can see how it's pushing down and the energy is

crushing the seamount itself.

The areas around the seamount, it's subducting very, very slowly, and it's

stopped because the seamount has actually physically stopped its

process. A massive underwater volcano became a doorstop.

Yeah. It can.

causes sticking points, and then ultimately there may be a major

slip related to that sticking point and the pressure that is built up over time

suddenly being released.

A violent earthquake caused by one of these seamounts could in turn trigger a

devastating tsunami, affecting the millions of people who live along the

coastline. If Victor can reach the bottom of the trench... he could gather

further crucial data to help predict earthquakes and tsunamis of the future.

The topography of this area of the Java Trench has surprised us a bit because

we're seeing what I would call sharp features, things that seem to come out

nowhere with some pretty steep drops or some pretty strong rises.

So it seems to be a pretty active area seismologically.

But after working overnight to solve the weight release issue...

The engineering team have been hit by another mission -critical fault.

There was a little pump that wasn't running.

And that's for when you come back to the surface, pumping that water out, give

you some buoyancy.

And when you leave, it'll help you go down.

Constantly trying to keep a running tab of everything so that nothing goes

missing. Because I'm very tired. We're all very tired.

Oh, it just went. It just went. Come up. Come up. Can they fix the new problem

before the cyclone ends the expedition?

All right, Tom, you've got a red light now that we didn't have earlier.

If we get this done, we can get out of this forsaken place.

The engineering team are under pressure to turn the sub around for a second

attempt on the deepest point of the Indian Ocean.

So, yeah, it's fixed.

Problem solved.

At last, the sub gets the all clear.

Biggest trick was trying to figure out what went wrong, but we worked it out.

We're throwing it back together.

Good timing.

Roller in.

Yeah, it's banking there.

Yeah.

The team release a first underwater probe, codenamed SCAP, to drop to the

deepest point of a narrow sinkhole and act as Victor's target.

They also drop a second probe a mile away,

outside the sinkhole, to gather additional data.

Okay, Victor, ready for you.

You shouldn't sit on the other side.

Sit on the other side, Tim. Thanks, man.

I'll stop. Here we go. We're getting the tow line off first.

Excellent detachment, gentlemen.

Okay, here we go.

With the thread of a tropical cyclone hanging over the expedition, this could

Victor's best chance to complete his mission and gather fresh evidence from

ocean's deadly tsunami trigger zone.

I've got a nice descent rate going.

These are places that since the dawn of time, no one's been there.

I'm getting to see it for the first time.

It's now been nearly three hours since Victor left the surface.

If we've dropped him in the right spot, you know, he should be pretty close to

right over the...

the target site. All stations be advised, coming up to the quarter hour

check, we do expect Victor is approaching the bottom.

I see the bottom of the display, 20 meters to go.

Seafloor is starting to come into view.

Coming very clearly into view now.

Brown and spackled, looks like a desert floor.

Surface, surface.

LF, at bottom.

At bottom.

Roger, LF. Understand.

On the bottom.

That was a lot of hard work.

Victor may be on the sea floor, but to reach the deepest point of the Indian

Ocean, he must find Skaff, the underwater probe the team have dropped

target. Okay, Skaffy, where are you?

Even at this extreme depth, in the pitch dark and crushing pressures, there is

life at the bottom of the Indian Ocean.

Amid a network of animal tracks, a sea pig, which can inflate its body with

water to float from the sea floor like a balloon.

A purple sea cucumber, munching its way through the sediment in search of

nutrients.

And one of its swimming cousins, drifting through the sub's life.

Victor can communicate with the probe to find out how far away it is, but not

its direction.

Okay, when I went south, it got a little closer.

West a little further.

Without the two other probes to help triangulate his position, Victor's task

will be far from easy.

There's a current down here.

I'm being pushed about a meter.

Come on.

all that. Come on.

It's like trying to find the Athena docking component of the Gemini mission.

swear it feels just like that.

Okay. Nothing on the sun.

Further on.

Surface. Bearing.

Gleam. Two.

Scaff.

He just transmitted.

He was saying something.

Did that sound?

If Victor doesn't locate the target probe, he will fail to complete his

attempt to reach the deepest point of the Indian Ocean.

Where are you, Steph?

And after a near three -hour descent and over two hours already spent searching,

time is running out.

Victor Vescovo is over 23 ,000 feet underwater in a sinkhole searching for

deepest point of the entire Indian Ocean.

To keep his global deep ocean mission on track, he must hunt for a target probe

dropped in advance of his dive.

But now he has lost communication with the expedition ship above. There's no

to guide him home.

Surface, surface.

Present depth.

Seven, three, four.

Five.

Say again.

Say again.

Because we may be on the shelf here.

It seems the steep walls of the sinkhole are blocking Victor's signal. I'd like

to relocate pressure drops to establish comms back over the op area.

Okay, Captain, we want to get the modem up and reposition right away. Yeah,

great copy.

Modem's in the water.

Surface, LF. 7,

3, 3, 9. You can breathe out now.

Roger, LF. We have you loud and clear.

I see you, buddy.

This is awesome.

I'm going to sit down right next to you, Scaf. How about that?

Touchdown.

Bottom of the Indian Ocean.

Bottom of the Java Trench. First time in history.

Pretty cool.

Surface. LF.

Present depth.

7, 3, 4, 2 meters.

At. Scaff.

Repeat. At. Scaff.

Understand. You found a spot deeper than before.

Congratulations.

The

underwater

probe is teeming with life.

Thousands of tiny crustaceans called amphipods are feasting on the bait.

These are the supreme scavengers of the seabed.

And arriving to join the feeding frenzy is an overblown cousin known as a

supergiant.

Its body has evolved to be large enough to discourage voracious predators.

Then an unidentified luminous jelly -like creature comes tantalizingly

casting an ominous shadow.

But the second probe, positioned a mile from the deep sinkhole and 2 ,000 feet

higher up, is filming an even more mysterious creature of the deep.

one that had never been seen by human eyes before.

With a bulbous, gelatinous head, and trailing a long strand with what looks

a weight on the end, this is an entirely unknown species of creature known as a

sea squirt.

Only further study and sightings could reveal the secrets of its bizarre body.

Request permission to ascend.

Victor has now completed the third dive of his epic five deep mission, helping

to unravel the mysteries of tsunamis that have devastated the Indian Ocean

to achieve new insights into life on the extreme edge of our planet.

We have a visual.

Welcome back, sir. We have you loud and clear. Thank you.

Welcome back.

Three down.

Seeing those creatures, seeing the Dumbo at that depth, and seeing this

creature. I've never seen anything like that. That's the weirdest thing I've

ever felt.

We're going to show people that there is a lot down here that we know nothing

about.