Original subtitles

Wade: Is our vital undersea cable network at risk

from forces beyond our control?

It could literally cripple

modern society as we know it.

Can new discoveries on the sea floor finally confirm

an explosive theory about the atlantic's most notorious

expanse of water?

Figueroa: Could this explain some of the stories

that we've heard about the bermuda triangle?

Wade: And how have a fortunate few gone over the world's

most famous waterfall and lived to tell the tale?

It's very, very unlikely that you

would survive going over the niagara falls.

Wade: The underwater realm

is another dimension.

It's a physically hostile place where dreams of promise

can sink into darkness.

I'm jeremy wade.

I'm searching the world to bring you

the most iconic and baffling underwater mysteries

known to science.

Shipwrecks can't just disappear...Or can they?

Wade: It's a dangerous, unexplored frontier that

swallows evidence.

We know more about the face of mars than we do

our deepest oceans.

Wade: Where unknown is normal and understanding

is rare.

[ sonar pinging ]

over the years, the bermuda triangle has been the scene of

the disappearance of dozens of ships and aircraft

and hundreds of people.

What is it about this area of ocean

that has made it so notorious?

Now, scientists are making big discoveries at the bottom of

our oceans that promise

to shed new light on some of the bermuda triangle's

most mysterious incidents.

On a calm spring day, a tugboat is sailing

from puerto rico to fort lauderdale,

florida, through the southern section of

the bermuda triangle.

Her experienced captain is resting below deck

when he receives a sudden call to come to the bridge.

The compass was spinning like mad,

and he'd never seen anything like that before.

Wade: A strange darkness descends on the vessel,

and without warning, all the tugboat's

electronic systems shut down.

Nothing electric was working.

The communications were all out.

Wade: The captain heads out on deck and is shocked

by what he sees.

The crew become aware that the sea around the ship

is boiling.

Zimmerman: The currents on the sea

are going wildly in different directions.

The crew are absolutely terrified.

Zimmerman: The fog is just so thick that he can't

distinguish between where the sky stops and the sea starts.

Wade: Fearing the worst,

the captain orders full speed ahead

to escape the churning waters.

Eventually, the tugboat breaks through the fog into

calmer seas and sails away from the danger.

The crew are at a loss

to explain what they have just experienced.

What could have caused this to happen?

We want to know what it is, and we want to know more.

Wade: One natural phenomenon that can have a dramatic effect

on the state of the sea is underwater seismic activity.

Volcanoes and marine systems

vary quite a bit, just like they do on land.

It can cause disturbances that can

affect the surface of the water.

Rondeau: In that case, what you actually have is heat.

They emit a huge amount of -- of gases,

and all of those create bubbles.

Wade: Underwater volcanoes have bean blamed for sea

disturbances and ship disappearances

elsewhere in the world.

But no volcanic activity was reported

in the vicinity of the tugboat incident.

So what else might be responsible?

Zimmerman: There are also underwater rock shifts that will release

unexpected waves,

unexpected currents.

But generally, those currents are not

associated with bubbling or boiling.

Wade: For the ocean to be as volatile

as the waters that surrounded the besieged tugboat,

it is thought that some other natural force

must have been at play,

and there is one prime suspect --

the highly combustible gas,

methane.

Wright: Methane deposits are mixtures of ice

and gas that are found in sediments

in the world's oceans, and we're finding more and more

of them.

Wade: Kept in an icy state by the immense pressure

and low temperatures at the bottom of the ocean,

methane, often in the form of solid compounds

called hydrates,

only needs a small disturbance to be unleashed.

Figueroa: You go to the bottom of the ocean, and you shake up

and you disturb the areas where the hydrates are,

and literally bubbles of gas

erupt from the bottom of the ocean

and start going up the water column.

Wade: So could releases of methane from the sea floor

have caused the appearance of a boiling sea around the tugboat

traveling through the bermuda triangle?

Zimmerman: By the time methane gas reaches the top surface,

it is going very rapidly.

That motion generates turbulence,

seemingly random motion in all directions.

Wade: But a boiling sea was not

the only phenomenon witnessed by the tugboat crew.

Their navigational instruments also malfunctioned.

When gas is followed close to a conductive surface,

they build up an electric charge.

It's known as the streaming potential.

It's an electric kinetic phenomenon.

Wade: This charge could have overloaded the tugboat's

electrical systems,

sending its instruments haywire.

The tugboat was then sailing blind, trying to get through

the dense fog,

possibly another effect of methane.

Zimmerman: Those small bubbles,

they've had the opportunity to hit

100% relative humidity, and they will release a fog

when those bubbles have burst.

It's a fog that should be fairly dense.

Wade: A methane burst seems the most likely cause

of the mysterious event experienced by the tugboat crew.

But could methane be responsible for

more deadly incidents in these notorious waters?

Figueroa: Could this potentially explain some of

the narratives and the stories that we've heard

about the bermuda triangle?

Wade: Terrifying a tugboat crew is one thing,

but causing the disappearance of whole ships

with all passengers and crew is quite another.

This would require an enormous force.

October 1985.

In the norwegian oil fields of the north sea,

a helicopter captures this extraordinary footage.

Routine drilling beneath a rig has

accidentally unlocked

a large pocket of natural gases, predominantly methane.

Huge quantities of gas roar up from the sea floor

with a force that threatens the stability of

the platform itself.

This phenomenon, known by oil workers as the burp of death,

is not uncommon in oil fields,

but could there be dangerous methane deposits elsewhere,

including in the bermuda triangle,

with the power to take down ships?

[ sonar pinging ]

[ sonar pinging ]

methane gas escaping from the sea floor is

responsible for a number of disturbing incidents at sea.

But could it be behind

mystery disappearances in the bermuda triangle?

The 1985 gas release that threatened an oil platform

in the north sea showed devastating force.

The incident was not a natural occurrence, however.

It was caused by intrusive human activity,

drilling for oil.

But could massive methane discharges like this occur

naturally and on a scale that could endanger shipping?

In 2017, researchers at the arctic university

of norway report a remarkable new discovery --

huge craters at the bottom of the ocean up to

half a mile wide and almost 100 feet deep.

The norwegian research indicates that you could have

large bubble bursts from the sea floor.

Wade: The giant craters found at the bottom of the barents sea

reveal what could be evidence of massive,

naturally-occurring deep ocean methane bursts.

Figueroa: These large methane craters were

the result of significant methane explosions.

The methane built up

in large amounts and then was released all at once.

Wade: Instead of a gradual release of bubbles

that causes the surface water to churn,

these craters suggest methane blowouts on a massive scale.

A single eruption can throw vast quantities

of methane to sea.

We're talking millions of tons.

Wade: A ship caught in such an event could be doomed.

The water would suddenly become much less dense due to

the sheer quantity of gas, sinking the vessel in a matter

of moments.

If a bubble occurred while a ship was directly above it,

it could be submerged into this pocket

of gas that is less dense than the water

that the rest of the ship is -- is on.

Wade: But this deadly gas from the bottom

of the ocean doesn't stop at the surface.

It continues to rise.

So if you have a crater that's half a mile wide,

releasing a burst of methane,

and what would it do to the air-sea interface

and the turbulence of the air above?

You know, what -- what would that look like?

Momentum doesn't just stop

when this plume hits the top surface.

It carries on into the atmosphere.

If your aircraft is above that, it will knock out the controls,

the communications, and, of course, the navigation.

Wade: And there's a further potentially

fatal threat to over-flying planes.

Methane is explosive, and if you have a huge pocket of it,

and an aircraft goes through it...

You know, we have all that static electricity

around 'em, as well, and if...

You just need a spark, methane, and it's surrounded by oxygen.

Wade: Faced with shocking evidence of the dangers

to shipping and aircraft,

scientists are racing to try and identify where large

reserves of methane may be located,

either in the form of gas pockets or solid hydrates.

Currently, researchers at the woods hole oceanographic

institute are using spectroscopy to identify

methane hydrates.

They've been using gas collection techniques

to actually measure

the amount of natural gas that's found on the sea floor

in different locations,

and they're measuring those gases to see what

their components are.

Wade: And the results for methane are startling.

Recent discoveries show that methane is incredibly

superabundant in the -- in the world's oceans.

Some estimate that it's as much as 70% of

the world's supply of methane is actually stored

under the oceans.

Wade: These undersea reservoirs are being discovered all over

the world,

including off the east coast of the united states,

but are there any in the seabed

under the bermuda triangle?

We currently don't have any evidence that large methane

buildups are happening

in the area of the triangle -- that's yet to be discovered.

Massive methane discoveries under our oceans add weight

to the theory that this gas

could be responsible for disappearances

in the bermuda triangle.

But with reserves being uncovered worldwide,

could methane be behind the mystery of missing ships

in other parts of the world, too?

Hidden on the bottom of our oceans

is a massive network of undersea cables.

These carry 99% of all internet traffic

and trillions of dollars of financial transfers every day.

They are the arteries that keep the modern world alive.

But an alarming incident in the early 1970s

suggest this network could be vulnerable to

mysterious forces.

August 1972.

A military aircraft from u.S. Task force 77 is

flying over southeast asia on a routine flight.

As it banks over the south china sea,

the crew sees a disturbance in the water below -- a large,

mysterious explosion bursting from the ocean.

This is a real mystery.

No one actually really knew what happened there.

Wade: The vietnam war is at a critical stage,

but there are no major combat operations in the area

at this time.

So what is exploding and why?

In an attempt to bring the war to a swift conclusion,

the u.S. Military has initiated a blockade of

north vietnamese ports.

All entrances to north vietnamese ports will be mined.

Wade: Huge numbers of powerful sea mines are deployed.

This was a huge operation done by the united states navy.

The sea was literally seeded with over 11,000 mines.

Wade: Floating on or just under the surface,

these mines lie in wait for any unsuspecting enemy vessel.

Any ships attempting to leave or enter

these ports will do so at their own risk.

Wade: But on August 4th, near the north vietnamese port

of haiphong,

something strange starts to happen.

These mines just start exploding.

The u.S. Navy has no idea why.

The over-flying u.S. Aircrew

observe 25 explosions in about 30 seconds.

But it's just the tip of the iceberg.

Elsewhere along the coast,

many hundreds of mines spontaneously explode.

When your weapons start going off,

that is a, you know, mystery that you want to get

to the bottom of.

Wade: What's behind this synchronized

undersea salvo?

Enemy action, a new superweapon,

or something from out of this world?

[ sonar pinging ]

[ sonar pinging ]

our vital undersea cable network is under threat,

and with it, the very future of the modern world.

And the key to understanding why lies

in a mysterious incident 50 years ago.

In August 1972, up to 4,000 u.S. Navy

mines mysteriously explode

in the seas around northern vietnam.

The question is what caused all of

these sea mines to self detonate for

apparently no reason?

Wade: The initial assumption of u.S. Investigators

is that the enemy must be responsible.

There is speculation that it may be the north vietnamese,

that somehow they've been able

to alter these mines autonomously.

Wade: But few believe that the vietnamese have

the technological means to pull off such

a coordinated feat.

It's not as though the vietnamese are sending out

underwater demolition teams and blowing these things up.

The naval officers in charge,

they have no idea why these mines were self-detonating.

Wade: With a north vietnamese plot unlikely,

the americans investigate further

and discover something intriguing.

Among the different mines deployed by the u.S. Navy,

only one specific type has blown up in large numbers --

magnetic mines.

These are mines which go off when they feel

a large disturbance in the magnetic field

of the earth.

As a ship passes through this, it affects the field.

It's a big lump of metal,

and it affects the magnetic field around it.

If it's a big enough effect, the mine goes off.

Wade: But no ships were spotted

in the vicinity of the explosions,

so there must have bean some other kind of trigger.

U.S. Navy investigators now strongly suspect

some sort of secret enemy weapon,

and for this, there is a precedent.

During world war two, british engineers were able to

trip magnetic mines by using huge electromagnets

attached to aircraft.

If you have a mine sitting here

in the earth's magnetic field, then all of a sudden, this other

artificial magnetic field comes through,

it will basically trip off the mine.

Wade: The vietnamese are not thought to have such means

at their disposal, but their cold war backers,

the soviet union, could, the americans suspect,

be using such aerial technology.

The first investigations were all focused on sabotage

and a secret soviet weapon,

which caused probably the cia to spend a lot of time

chasing its own tail.

Wade: Having found no evidence of an electromagnetic

superweapon, the u.S. Navy investigators are left

scratching their heads.

But then, in a strange twist,

reports emerge from further afield indicating that they've

been looking in the wrong place all along.

Elsewhere in the world,

other unexplained phenomena have been occurring.

We know that this kind of thing was happening not just

with these mines, but with other things.

Clarke: At the same time as the mines went off in vietnam,

there were actually reports of electromagnetic disturbances in

the philippines, brazil, japan.

In america itself, power companies were

reporting failures.

The power systems went completely haywire.

Wade: There's only one thing known to meddle

with the earth's magnetic field

with such force --

the sun.

The magnetic mines are set off by

a magnetic anomaly, by a solar flare.

Wade: A solar flare is an explosion of energy

on the surface of the sun.

It can trigger what's known as a coronal mass ejection,

which blasts an immense cloud of magnetized particles out

from the sun at over a million miles per hour.

If the earth happens to be in its path,

strange things start to happen.

It can cause alterations in the earth's magnetic field.

Wade: If the magnetic flux caused by the sun

matched that of a large metal ship

passing near the sea mines,

it could have triggered the underwater explosions.

For researchers, this was sort of a smoking gun.

Wade: The explosive events of 1972 were shocking enough,

but a similar solar event today

could have a far more wide-ranging impact,

devastating our vital underwater communications.

If we had a massive solar flare, it could literally

cripple modern society as we know it.

[ siren wailing ]

[ sonar pinging ]

[ sonar pinging ]

explosive events in 1972 showed conclusively that

solar storms can have a dramatic impact here on earth.

But new evidence suggests that their effects can penetrate to

the very bottom of our oceans with potentially

devastating consequences.

Electromagnetic radiation from a solar flare can have

implications for radar and communications at sea,

but it also has the potential to affect undersea cables.

Wade: Hidden along the bottom

of the world's oceans and connecting the continents

lies a network of submarine cables.

Polakowski: All this data that we're sharing

and transferring doesn't get thrown up through satellites.

It all goes through subsea cable systems.

Those are really the conduits of the modern information age.

Wade: 21st century life

on earth relies on 3/4 of

a million miles of undersea cables -- every day,

these carry $10 trillion worth of

financial transfers and 99% of internet traffic.

Data doesn't move through the cloud,

it moves under the ocean.

We sometimes think that they are, since they're so deep in

the water, that they're not affected by these solar storms,

electromagnetic kind of disturbances.

But what we're finding now is that

they are actually being affected by these things.

Wade: Many experts now agree that a large-scale solar event

could cripple our essential underwater cable network,

causing unimaginable disruption to our daily life.

We cannot rely upon

the sea to protect our communication systems.

If we have another solar flare,

if there is another event similar to that of 1972,

then that could wipe out global communications for days,

if not weeks, causing untold trouble for millions.

Wade: The question is not if,

but when the next solar storm will hit us.

It's turned from a mystery into a nightmare.

♪

♪

wade: The world's great waterfalls combine

awe-inspiring beauty with

terrifying power and the dizzying prospect

of certain death.

On rare occasions, however,

people do survive such chance-in-a-million cascades.

But how does anyone overcome the most

feared and famous falls on the planet?

How does anyone survive niagara?

May 21, 2012.

A man in his early forties climbs

a railing near the top of niagara falls

and jumps in.

He disappears into the torrent and is swept over the top.

Emergency services are scrambled to recover

what is assumed will be his dead body,

but when they arrive at the foot of the falls,

they are amazed to discover him alive.

The survivor is hauled back up the cliff

on a stretcher and airlifted to the hospital.

There, doctors treat him for broken ribs

and a collapsed lung,

but he lives.

Of the estimated 5,000 people who have gone over

niagara falls,

the middle-aged man is one of just 13 who have survived.

Statistically speaking, it's a very,

very unlikely event that you would survive going over

the niagara falls.

Wade: Is it luck? Is it a miracle?

Or can science help us understand how

a fortunate few have survived this deadly drop?

Astonishingly, some people have, for whatever reason,

gone over these falls and survived.

Niagara falls is a thunderous cliff on the american-canadian

border that sends an icy torrent

plunging 188 feet down into a churning mass

of frothy water and jagged rocks.

This natural wonder is thought to be the fastest flowing falls

in the world,

with over six million cubic feet of water rushing

over the edge every minute.

Tuttle: Niagara falls is absolutely spectacular,

hundreds of thousands of tons

of water crashing over the escarpment.

Figueroa: It's powerful, it's fast.

There's a lot of force.

It's cold -- it's one of those amazing places on earth.

Wade: Despite the obvious dangers,

there is a long history of people throwing themselves over

the great falls at niagara to see if they can survive.

People get mesmerized, and they're curious.

Can I survive it?

How could I survive it?

Is it even possible to survive it?

Wade: The first known successful attempt was made by a woman

called annie edson taylor,

a 63-year-old teacher from auburn, new york.

Annie taylor decides that she is

going to be the first to survive

going over the niagara falls purposely in a barrel.

She had a mattress wrapped on

the inside of the barrel for cushioning,

went over the falls, survived it, and was therefore

the first person to successfully go over the falls.

Wade: Annie taylor survived with just a cut and bruises,

but her first words when she surfaced

after the death-defying feat

were a warning to others...

"no one ought to ever do that again."

but they did.

People started to go over the falls in barrels.

People come up with inventive ways

to go over niagara falls -- metal boats.

One guy used inner tubes.

Man: I guess it's the same reason

why people want to climb mountains.

The falls was there,

and he just wanted to conquer it.

Some people go over because they want to be daredevils.

Some people go over just 'cause they're crazy.

Wade: Daredevil attempts carried out using some form of safety

equipment like barrels make up the majority of

niagara survivals.

But even more remarkable are the handful of survivors who

have made the great leap without any form of protection.

How could anybody survive such a fall?

[ sonar pinging ]

[ sonar pinging ]

as far as we know, only 13 people have survived

a leap over niagara falls,

the majority in protective barrels,

but a handful have gone over without any form

of protection and lived to tell the tale.

Goodman: It's kind of a mystery why

those people survive while other people don't.

There are a number of factors to bear in mind here.

So firstly, there's the sheer height.

Wade: At 188 feet, niagara is higher

than the leaning tower of pisa.

188 feet, icy drop to the bottom --

no, thank you.

Wade: But remarkably, unprotected jumps into water

from an even greater height

have been survived.

In 2015, laso schaller jumped into a lagoon

in switzerland from a height of 192 feet.

He came out unscathed.

But schaller had carefully selected his jump point

and could control exactly where and when

he hit the water.

A jump into the mighty torrent

of niagara is far less predictable.

Goodman: At the bottom of the falls,

there are some areas that are rockier

and some areas that are less rocky.

Wade: And there are other odds stacked against

a niagara jumper.

There's the shock of the hitting the water.

The water is cold, it's freezing.

How long do you have before you're at risk for hypothermia?

There are so many things working against you here.

Wade: But certain things are as applicable to successful

niagara jumpers

as they are to any other high divers.

Body position on water entry is critical.

It seems as though many of them enter the water feet first,

perhaps on the tips of their toes,

which is protecting their brain from a brain injury,

and therefore, they go much more easily into the water.

Wade: And high divers have another trick to survive

hitting the water.

They will tighten up their muscles really, really tight,

and this will help them avoid

any sort of injury to their organs

or their other muscles by going --

entering the water in super-tight form.

Wade: The maelstrom of water at the bottom of

the falls could also offer an initial advantage.

Tuttle: There is a giant

washing machine creating air bubbles down there.

Wade: Hitting static water at speed

is like hitting a solid object,

but aerated water provides far less resistance,

and because of this, high divers often rig

air tanks into their dive pools to soften their entry.

But there is a downside to this aerated water.

You are not going to be able to swim in that

low density, almost, water.

You can't get to the service, you try to breathe,

you're gonna breathe in water and air.

You're gonna drown.

Wade: In addition, the water thundering down from the falls

creates lethal eddies and whirlpools,

making the freezing water completely unpredictable

and whipping debris around at up to 30 miles per hour.

There's a dynamic movement of water when

you get to the bottom of the falls.

We're talking whirlpools and currents,

so it's not like you can even physically swim.

The water beneath 'em churns, and it will push you under,

and most people want to come to the surface immediately.

What people need to do is actually swim down

below to be able to get kicked out.

Most people who go over the falls don't know that,

and, you know, if you're stuck, you drown.

Wade: But against all the odds,

somehow, it is possible to survive this lethal descent.

It might be a combination of luck, um,

and chance and physics.

You just kind of never know.

A lot of things have to play together.

We'll probably never really understand how a small number

of men and women have endured

one of the most powerful forces on the planet

and lived to tell the tale.

But for me, the best way to survive niagara

is to never even consider jumping in the first place.

♪

[ sonar ping ]

♪

although statistically safe, the history of sea travel is

awash with mysterious dangers,

sudden storms,

pillaging pirates, even sea monsters.

But could there be a new danger out there

on the high seas?

A secretive force that arrives without warning,

causes huge destruction, and disappears without trace

back into the deep?

June 13, 2019.

The norwegian-owned oil tanker, front altair, is

sailing in international waters near

the strait of hormuz

on a routine voyage from the united arab emirates

to taiwan

when suddenly the ship is shaken by a powerful impact.

[ alarm blaring ]

elliot: The ship is smothered in smoke.

Clearly, something dramatic has happened.

Wade: The ship's crew have no time to launch any lifeboats.

Clarke: Smoke is so thick that the crews decide

to radio for help and abandon ship as quickly as they can,

avoiding normal procedure and just getting to sea

to get away from their ship.

Wade: The tanker is carrying 75,000 tons of

naphtha, a flammable liquid hydrocarbon mixture.

It could be an accident, so something's exploded

on the ship accidentally.

The front altair's crew are still in the water when

the nearby u.S. Fifth fleet

receives a second distress signal from

a different ship.

It soon emerges that another attack has taken place

on a similar vessel

of another nation in the region,

raising the specter of a concerted campaign being

carried out against shipping

that is vital to the world economy.

Can this be a coincidence? Probably not.

Polakowski: When you see these kind of attacks that are very similar,

they're very close in time,

you have to start asking questions.

Are they related?

Are they coordinated?

Wade: Fortunately, no one is seriously harmed.

But these multiple explosions are no accident.

Soon, it becomes apparent a major incident has occurred.

Wade: Who or what is behind this coordinated series of attacks?

A military assault on a large ship

would normally utilize missiles or torpedoes.

The moment they see smoke, the moment they see a ship

belch fire, they think it's been hit by a missile.

Wade: But this is not a conventional military attack.

Wade: The damage bears the hallmarks of magnetic mines.

Explosive devices attached to the hull,

the outside of the ships, which had been set off by --

either via timer or remotely.

The damage at the blast hole

is consistent with a limpet mine attack.

Polakowski: A limpet mine is a portable small explosive

that can be stuck to, in this case,

a hull of a ship.

Wade: Which means this deadly military hardware

was placed in position.

So who put it there?

[ sonar pinging ]

[ sonar pinging ]

mysterious coordinated attacks on two tankers in

the strait of hormuz have investigators baffled,

and it turns out this is not the first time it's happened.

Clarke: A month earlier to the day, four other

huge supertankers had sustained similar damage

in other similar attacks.

The theory about coordination becomes even more likely.

Wade: Billions of dollars worth of oil are shipped through

the strait of hormuz every year,

and as a result, this is one of the most closely monitored

sea areas on the planet.

So if the perpetrators of the attacks were using boats,

they would have been spotted.

But could they have been using remote underwater vehicles?

Was there some kind of submersible or some kind of

underwater mechanism that is being used

to attack these ships?

Wade: Underwater vehicles are usually operated

via a control line,

which makes clandestine use over distance

difficult to impossible.

Only one other obvious option remains that can operate

above and below water with such stealth and precision --

specially trained divers.

Elliot: These are very highly skilled frogmen,

highly trained military individuals.

These are elite warriors.

Wade: The identity and true motives of

the attackers remains shrouded in mystery.

You cannot prove who they are.

The equipment will be internationally sourced.

They will all disappear.

No nation will acknowledge who they are.

You actually have to physically catch them

to be able to prove who they belong to.

This is a region absolutely rife with tension.

The blame game begins. Who did it?

Iran does have a track record of

causing trouble in the straits of hormuz,

however, they cannot be ruled as the only potential actor.

There are terrorist organizations around the world,

some of whom have developed marine wings

which are specializing in this sort of operation.

Wade: Could an unknown terrorist network

be responsible for these maritime attacks?

We're used to seeing terrorist acts on land.

We're not used to seeing terrorist acts at sea,

and especially in the stealthy undersea environment.

This could be a really scary new development.

Wade: As airports have become more secure,

are terrorists turning to ports and shipping as the new

targets of choice?

The theories with frogmen, especially with the growth in

diving as a hobby

and as an industry, is that these skills are actually

becoming more and more available,

and terrorist organizations developing marine wings

with these capabilities.

Wade: The world is now waking up to this new threat.

But how do you stop an underwater terrorist?

Polakowski: The only really way that they're gonna be able to

protect themselves is getting

a full picture of what's happening under the water.

So now, with technology like sonar, electro-optics, radar,

we're actually able to see a real-time view of

the underwater environment.

Wade: But while port defenses can be stepped up

relatively easily, the risk of terrorist attack

out on the open ocean remains.

Clarke: Are we heading to a future where

these are gonna get more frequent,

where there's gonna be more and more incidents in

the maritime sphere that impact upon global trade?

Wade: Terrorism worldwide is constantly adapting

and evolving,

finding new ways of wreaking havoc in new

and unexpected places.

The 9-11 terrorists turned civilian airliners into

lethally effective missiles,

killing thousands.

So if the threat of deepwater terrorists isn't countered,

what might they do in the future with, say,

a supertanker full of oil?