Original subtitles

[ suspenseful music plays ] wade: Can an incredible

underwater discovery in the arctic

tell us what happened to the ill-fated franklin expedition?

Potter: You feel like somebody or something

is over your shoulder.

Polakowski: Who knows what we're gonna find inside?

What is the secret behind the mystery craft

speeding towards the u.S. Coast?

And is there a new killer lurking in the depths?

It's not something that you can hear.

It's not something that you can see.

It's not something that you can smell.

Just like, "oh, my god.

I'm not getting in the water."

[ thunder rumbles ]

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 ]

-- captions by vitac -- www.Vitac.Com

captions paid for by discovery communications

♪♪

in my years of investigating underwater mysteries,

I've been to some pretty hostile places

and the frozen waters of the arctic

are some of the toughest I've ever experienced.

It's a place where the mind can play tricks on you.

Now, reports are surfacing

of locals claiming to have seen ghosts from the deep.

Could a dramatic new discovery

solve one of the greatest arctic mysteries of all time?

♪♪

2014. The canadian arctic.

A team of marine archeologists find a warship

resting on the sea floor of king william island.

Potter: Finding it was extraordinary.

You could see this ghostly ship.

Wade: Then, a second ship is located.

It's as if the crew has just stepped out.

You could see shells inside and things still stacked up.

It's very exciting, but it's also a bit unnerving.

Wade: These are no ordinary shipwrecks.

They all the hms erebus and hms terror,

two ships from the ill-fated franklin expedition.

They've been missing for over 170 years.

They were not where anybody expected them to be.

Wade: Finding the ships is a remarkable discovery.

But what happened to their missing crew?

Out of the 129 crew members

that set out on the franklin expedition,

no one came back.

♪♪

wade: When the expedition sets out in 1845,

expectations are huge.

Sir john franklin and his crew

are on a mission through uncharted arctic waters

to find a navigable passage

between the atlantic and the pacific.

♪♪

the northwest passage is a kind of a shortcut,

the holy grail of its time, in terms of exploration.

It's kind of like the space race of the 1960s --

which nation will have pride of place?

Wade: Franklin is one of the most celebrated

naval commanders of the day.

Sir john franklin -- he was an honored naval veteran.

He had fought with nelson at trafalgar.

He's referred to as king arthur in the british press.

That's the kind of reputation he had.

Wade: Franklin's team

has the most advanced technology available.

They had enough provisions to survive

a very long time out at sea without resupplying.

They actually even had heating systems within the ship

to keep the crew and the boat inside

warm enough during the expected arctic winters.

It was a very well-equipped expedition,

with very experienced men,

so there's no reason for them to expect to fail.

Wade: But they do fail.

And, for almost two centuries,

the fate of the expedition has remained a famous mystery.

The arctic waters have revealed very little evidence

of what happened.

In 1850, another expedition is sent to find them.

Potter: They located franklin's first winter camp

and, a few days later, walking along the beach,

they saw three graves of franklin's sailors.

Wade: Franklin's crew were not alone on the ice.

The canadian arctic is home to the netsilik inuit.

A group of inuit are later found

with items belonging to the crew.

Spoons; knives; forks; broken chronometers;

franklin's medal of knighthood itself,

which is seen in the photographs before he sailed.

It's not something you would just give

to the local people as a gift.

Wade: Then, 14 years after the expedition set off,

there's a breakthrough.

An official document is found,

with a handwritten explanation

of how the ships became locked in the frozen waters

for 19 months.

It indicated that they had abandoned the ships,

there were 105 survivors,

that franklin himself had died the summer before.

Wade: With franklin dead, on April 22, 1848,

the crew abandoned their ships and set out on foot.

Why did they decide to leave the ships when they did?

To leave the one spot that you know that is warm,

that has food and shelter, to set out on the ice,

you have to be extremely desperate.

Or maybe even a little bit crazy.

Wade: 105 men leave the ships.

None are known to have survived

and fewer than 40 skeletons have ever been found.

Over the years, there have been

many different theories about what happened to them.

Scurvy, of course, would've been a factor.

The inuit encountered them.

They talked about men with black gums,

from frostbite and scurvy, probably.

You start out with scurvy.

Then, you've got tuberculosis.

These are the two big killers of the era.

Wade: The extreme conditions would have been physically tough

and long periods trapped in the arctic sea

can also cause something psychological

called winter-over syndrome.

Elliott: Just nothing but ice, nothing but snow.

For months and months, you can see nothing.

You know nothing about what's going off around you.

You become very isolated.

You become very disorientated

and you start behaving in a very bizarre way.

Wade: This could explain one mysterious account.

An intuit group report trying to help some of the crew

by building an igloo and supplying seal meat.

But, later, they find the igloo abandoned

and the meat untouched.

The inuit tribes out there were equipped

to survive in these kind of conditions.

They offered help and the crew rejected it completely,

which is quite strange, when you're so desperate.

Wade: That they would reject food is even more surprising,

in the light of a troubling story that emerges,

suggesting that the crew turn on each other

in order to survive.

The inuit accounts of bones that had been sawed

or broken open to get at the marrow.

Similarly, skulls that had been broken open.

There is hard archeological evidence of cannibalism.

When they started analyzing these bones,

they had cut marks.

Not scratches from wounds, but butchering marks.

That indicates that there could be

some kind of cannibalism taking place.

Wade: What would've caused this well-supplied crew

to resort to cannibalism?

♪♪

for almost 200 years,

any evidence discovered about the franklin expedition

has raised more questions than answers.

Can we use new science and technological tools

to help us answer that question?

Wade: Bodies from the three graves found at the first winter camp

are exhumed.

They are eerily well-preserved by the ice

and analysis reveals something unusual.

They were subjected to on-site autopsies, x-rays,

chemical tests, and so forth,

and a conclusion was that lead might, in fact,

have been the overall culprit of the expedition.

Wade: Lead poisoning in the middle of an arctic wilderness

sounds unlikely,

but could it have come from something on their ships?

One of the new technologies the expedition carried

was tinned food.

Over 8,000 cans of it.

We knew that the ships were supplied with tinned food

and it was shown also that the tinned food

was prepared in a great hurry.

And tins had a very thick layer of lead inside.

They would use lead to seal the tops.

High concentrations of lead can be deadly.

It can lead to a debilitating mental state.

It decreases brain functionality.

Wade: Lead poisoning seems to stack up,

but the evidence is not conclusive.

♪♪

could an innovative type of x-ray technology

tell us more?

X-ray fluoroscopy shoots x-rays at things

and looks at their fluorescence.

This allows scientists

to look at the micro structure of the skeletal remains.

We're trying to just really get a much more detailed map

of lead in the bone and that's the technology

that has given us that high-resolution image.

Wade: Unlike a conventional x-ray, fluoroscopy can tell us

how much land is in the bones and exactly when it got there.

Can separate new growth from old growth.

We can color-code that growth by lead levels

and we can see what's the difference in the new growth,

as opposed to the old growth within the bone.

Wade: High lead levels in new bone would mean

the men were exposed to it just before they died.

Could this finally solve a mystery

that's remain trapped in these frozen waters for centuries?

[ sonar pinging ]

[ sonar pinging ]

the franklin expedition is one

of the most baffling mysteries I've ever come across.

129 experienced men armed with the latest technology

and three years worth of food set out across the arctic sea

to discover the fabled northwest passage.

None of them come back

and no one knows what happened to them.

To find out, scientists are testing

the well-preserved bodies of three of the crew.

Were franklin's men poisoned by the tinned food

that was meant to keep them alive?

This new analysis suggests not.

The shocking discovery is

that what we had thought was the explanation

is not really the explanation anymore.

There weren't higher levels of lead

in people who had been presumably exposed to it longer

and, indeed, that the lead probably did not come

from exposure experienced during the expedition.

Wade: X-ray fluoroscopy reveals that the high lead levels were

in older bone growth,

suggesting the men were exposed to it

via industrial pollution before they left home.

It doesn't look like lead poisoning is the smoking gun.

Wade: So, if it wasn't lead that killed them, what was it?

For almost two centuries, there's been little to go on.

We wonder how, given the diligence of the search

over more than a century and a half,

we've found so little.

Why isn't there more?

[ static crackles ] wade: But the recent discovery of franklin's ships,

preserved beneath the ice,

should prove a major breakthrough.

Many of us who've been studying this for years

thought the odds of actually finding one

of these ships are low.

We imagined they were probably just

smashed to pieces in the ice.

Wade: Surely, now, all the questions can be answered.

No one has set eyes on these ships in almost two centuries.

Now, a team of marine archeologists is surveying them.

Polakowski: The terror is eerily intact.

Who knows what we're gonna find inside?

Mckay: The conditions for preservation are very good

because you have depth and you have less light

than you would at shallower depths

and the cold temperature of the water really helps.

Wade: But not everyone is happy

about the underwater investigation.

Within two weeks of the team diving on the wrecks,

six people in the local inuit town die.

In a small community, that's a lot of deaths

to happen in a short period of time,

so, some people began to speak of a curse of franklin.

Wade: Some believe the spirits of franklin's men

have been released from their watery grave.

Polakowski: The local tribes even speak of shadowy figure

walking the beaches and the ice where the ships once were.

I think there is still a kind of

a spectral feeling to the arctic.

♪♪

wade: Local superstition is not the only factor

making investigation difficult.

The freezing underwater conditions and the location

limit the divers' season to just three weeks a year.

♪♪

remote cameras have to be used to explore inside the ships,

so investigators can see, but they can't touch.

But could these submerged ships finally unlock the mystery

of what happened to franklin's expedition?

It may well be that there'll be records,

of some way, shape, or form that have survived on the ship,

which will give us some insight.

Potter: Drawers, they're dark.

There's no oxygen content in there.

There's no marine life and there is every chance

that we'll actually get written records of what happened.

There's captain crozier's desk,

still sitting there, a bit of silt on top of it,

looking as though you could just open one of the drawers

and find the answer to all of the mysteries.

Wade: It could still take years, but, hopefully, one day,

we can open that drawer and finally discover the truth.

♪♪

[ sonar pings ]

July 4th weekend, 2019.

A man goes into the ocean off a popular tourist beach

on florida's emerald coast and comes out feeling fine.

48 hours later, he's dead.

Was it something in the water

and, if so, can forensic science

help us track down this killer on the coast?

♪♪

our beaches are where we go to relax and have fun,

but what if there's an invisible killer lurking just offshore?

There's something out there

that people don't even know is out there.

You can't smell it.

You can't see it.

You can't taste it.

It's terrifying.

Wade: Doctors are initially mystified

by the death of the florida man.

But laboratory tests finally reveal the killer's identity.

Not a stealthy new predator,

but a microscopic, deadly bacteria.

Figueroa: Once inside,

this starts devouring and eating human tissue.

If it's not stopped in time,

the only course of action is amputation.

If we can't get it out, it can also lead to death.

The idea of contracting a flesh-eating bacteria

in water that you swim in is the stuff of horror movies.

Wade: Where did this flesh-eater come from,

has it risen from the hidden depths of the ocean,

and can we stop it before it's too late?

[ sonar pinging ]

[ sonar pinging ]

evidence suggests there could be

a new killer lurking in our oceans,

a deadly bacteria that eats its way

through flesh and internal organs.

What can be done to stop it spreading?

♪♪

can this new bacteria be stopped?

Are we gonna end up shutting down our beaches?

Wade: Science has some of the answers.

♪♪

this particular bacteria likes low salinity,

warm bodies of water,

often found near coastal regions where humans frequent.

Wade: A deadly waterborne bacteria

that hangs out in the same place as we do

is a frightening thought.

And this one has a name --

vibrio vulnificus.

Research suggests it's transmitted to humans

through open wounds or by eating shellfish,

and it's particularly dangerous

to those with a compromised immune system.

The problem is is that, when it mutates

and becomes harmful or active to humans,

it can cause sepsis.

Wade: Sepsis is when the body's immune system

[ monitor beeping ] overreacts to an infection

and starts to attack its own tissues and organs.

It can quickly prove life-threatening.

The centers for disease control

estimates that about 80,000 people per year

are stricken with this illness.

People get out of the water

and they feel fine for a few days

and then, all of a sudden, your leg starts to swell up

and, within hours or days, it's cut off.

Wade: And it may not just be affecting all beaches.

♪♪

in June 2019,

there's a new case reported.

An experienced water sports guide

is paddling across an inland florida lake.

And, later on in the day, he noticed

that his arm had swelled up significantly

and, as the day went on, it got even worse.

He's not immersed in the water.

It's not in his eyes.

It's not in his ears.

Wade: Could it now be possible

to get infected by the bacteria

without even getting in the water?

Scientists are now more concerned with it

because it seems to be mutating

and it seems to actually be more common.

It's finding new ways to infect.

Wade: Significantly, the paddleboarder had been on the lake

many times before without any problems.

The worrisome thing is that people are starting

to get infected where we haven't had cases of this before.

Tuttle: It's out there.

It's spreading.

Tuttle: Is this a result of global warming?

Is it issues with pollution in the water?

What are the issues that are creating it?

Wade: New infection sites are being discovered all the time.

♪♪

rising sea temperatures mean more and more coastal regions

are now potential breeding grounds for the bacteria.

The warmer the ocean,

the better the conditions for bacteria.

Wade: Most bacteria don't travel across large bodies of water

because colder currents kill them off,

but a new insight suggests

human activity could be responsible

for transporting this underwater killer worldwide.

Over 90% of everything in our homes comes to us by sea

and vast cargo ships don't just transport our global goods.

They may also carry flesh-eating bacteria.

Large ships now take on water as ballast.

They suck up water in this port

and then, when they get to another port,

they empty the ballast tanks whilst they're offloading.

So this means there is a constant flow of water

being carried around the world on our global shipping network.

Wade: A never-ending flow of ships

carrying tons of water from country to country.

If this is how the vibrio bacteria is being spread,

it may already be too late.

This invasive bacteria has the potential

to become a global health crisis.

The vibrio bacteria can be treated with antibiotics,

[ monitor beeping ] if administered quickly,

so medical teams need to be alerted and prepared.

But with 70% of the world covered by water,

it's almost impossible to know

where this invisible killer will strike next.

Figueroa: Perhaps we can use the tools of science and technology

to better predict where these outbreaks might occur.

Wade: There is one pioneering technology

that could help us stay a step ahead.

Computer modeling can be used to create simulations

of where the vibrio bacteria might appear next.

Scientists are using satellite technology

to track salinity,

ocean currents, and temperature.

To try and map global trade and global currents

and see where they're gonna come,

so they can move the resources to be there.

Will these new, predictive techniques be enough

to help us defeat an invisible killer

or are we heading towards a world

where it's no longer safe to go into the water?

♪♪

[ sonar pings ]

in pirate stories of old, finding buried treasure

is always about a map where x marks the spot.

In the deep water realm, however,

things are rarely that simple.

But could new underwater technology

do away with treasure charts and help to locate

what's possibly the greatest pirate's haul in history?

Could the treasure have been right under our noses

the whole time?

♪♪

wade: The mystery starts

with an infamous caribbean pirate

called captain henry morgan.

Captain morgan is not just a rum bottle.

He is actually a real person

and he's a real living legend, in his own time.

In 1671,

morgan sets out with 36 ships

to raid the spanish-controlled city of panama

and steal its gold.

Panama was one of the richest cities

in south america at that time.

Wade: It's the biggest heist of the age.

He carried off 134 horse-loads of gold and silver.

Wade: But then, something unusual happens.

According to one account,

morgan, unbeknownst to most of his men,

sneaks back onboard

and leaves panama with just three ships.

It is possible that he may have beat a hasty retreat

because he had a ship full of treasure

that he wanted to keep for himself.

Wade: When morgan arrives back home, in port royal, jamaica,

he has only one ship,

and a fraction of the loot.

What happened to the rest of the treasure?

Did captain morgan make away with a lotta loot

and, if he did, where did he stash it?

Clarke: There were all sorts of rumors about where the treasure

had been placed, what he'd done with it.

Wade: For over 300 years, people have put forward theories

for the possible location of morgan's missing treasure.

But, now, a team of underwater archeologists

have discovered a shipwreck near panama,

and it's on the route morgan would have sailed.

It was associated with morgan's adventure

because the material on the ship dated to that period.

Could this mystery shipwreck be the underwater hiding place

for captain morgan's missing treasure?

[ sonar pinging ]

infamous pirate captain morgan makes off

with a fortune in silver and gold.

But when he arrives back in port,

most of the loot has mysteriously disappeared.

Where is captain morgan's missing treasure?

New underwater investigation techniques

could finally uncover its hiding place.

Polakowski: The question is, did captain morgan

make away with a lot of loot?

And if he did, where did he stash it?

Wade: Some archeologists believe that a shipwreck found near panama

could be one of morgan's fleet.

Polakowski: They found cannons and chests.

But after further analysis, they actually figured out

that this was more likely a spanish ship.

So, while these new ships

and new evidence comes to light,

really all it's doing is it's furthering the mystery.

Wade: So if the treasure's not on this shipwreck,

where could it be?

An interesting detail and accounts all the time

could give us a new lead.

Captain morgan takes several weeks

to get from panama city back to port royal,

much longer than expected.

Elliot: Could morgan have stopped on his way back

to port royal?

Polakowski: Because he's a pirate, he doesn't have access

to normal ports, so he would have to be

very careful where he's gonna make his stops.

Wade: There is one possible location.

Elliot: On the route back from panama city to port royal,

you have this island called san andrés.

Wade: San andrés is a small coral island in the middle

of the caribbean sea,

reputed to be a favorite of morgan's,

speculated that he might have unloaded some of his cargo

and spoils there.

Mckay: Given the strength of the winds,

they may have had time to stop and unload a ship.

Wade: San andrés is strewn with sea caves,

making it an ideal place to hide treasure.

There are all sorts of rumors that he managed

to find a very deep cave

and stored all the gold down in there.

And that has been a site of many treasure hunts

for many years ever since.

Wade: Despite many searches over the years,

no sign of morgan's missing treasure has ever been found.

Perhaps the solution lies closer to home.

Another theory that has always been present

is that actually captain morgan kept the treasure with him,

and it came back to port royal with him.

Mckay: If you lived in jamaica

and you wanted to spend your money,

you'd keep it somewhere nearby.

You know, you don't want to have your closest atm

1,000 miles away.

It just doesn't make sense.

Rondeau: Port royal was really the pirate haven of the caribbean.

And really, it's the setting for the modern-day view.

We have of what pirate life was like.

Wade: Morgan lived out the rest of his days in port royal,

where he was buried,

taking the secret of the missing treasure to his grave.

Then, four years later, a natural disaster

engulfed the city.

It actually sunk into the sea

after an earthquake and a tsunami hit the region.

Wade: Did morgan's treasure end up under the sea?

Mckay: The potential could be that morgan hid it

somewhere around the city.

And once that disappeared beneath the waves,

so too did the treasure.

Wade: Now a team of marine archeologists has begun to map

the underwater remains of the sunken city.

There more or less intact is an archeological site

to be investigated properly.

Wade: Perhaps this new research will finally

locate captain morgan's hidden treasure.

One of the techniques being used is photographer.

Photogrammetry is a survey technique,

a remote-sensing technique.

Polakowski: You go and take photos of an area or an object

and you kind of go around it.

And it's an algorithm essentially

that meshes all these photos together

and creates a 3-d object.

Wade: It's only recently been developed

to map underwater sites.

The team can create a 3-d picture

of what the city looked like

when it disappeared under the waves

three centuries ago.

It lets you reach out and touch history.

It's pretty cool.

Clarke: If we can accurately create a map

of captain morgan's period,

then that gives us an idea of where such treasures

might have been hidden.

Wade: It's early days, but when the map is finished,

it should be possible to pinpoint where morgan lived.

Could the hiding place of his famous missing treasure

be uncovered at last?

In the underwater ruins of port royal?

This isn't like finding a pirate ship.

It's finding a whole pirate city.

So who knows what you can find?

♪♪

wade: The pacific ocean

is the largest and deepest ocean on earth.

It's a place I've come back to time and again

to investigate the mysteries beneath our waters

because it's the perfect place to hide.

June 18th, 2019,

the u.S. Coast guard are in pursuit of a mystery craft

heading north off the coast of ecuador.

It's sitting low in the water,

barely visible above the waves, and moving fast.

The coast guard has been tracking it for 12 hours.

Could it be a new military prototype?

But whose?

And why is it here in the pacific ocean?

The sub's crew don't seem to realize

that they're being chased.

Rondeau: The operator of this vessel is looking forward.

He can only see one 100 yards in front of him.

He's not even aware that the u.S. Coast guard

has surrounded him.

It's gonna be hard to get on.

Wade: To solve this minisub mystery,

they're going to have to jump onto the moving craft.

Wade: June, 2019.

The u.S. Coast guard is tracking an unidentified vessel

traveling at speed through the pacific ocean.

It looks to be heading for the u.S. Coast.

Could it be some kind of secret weapon

or something else?

Coast guard officers have been trying to stop the craft

with no success.

So finally, two marines jump on board.

[ indistinct shouting ]

as well as its frightened crew of five,

the vessel contains cocaine with a street value

of $232 million.

The mystery craft is what's known as a narco sub.

Narco sub is a pretty rudimentary submarine

built by drug cartels

to smuggle drugs from south america to north america.

Wade: The business of trafficking billions of dollars

of illegal drugs to the u.S. Has gone underwater.

The coast guard have stopped this one.

But how many more of these homemade subs

could be making their way undetected to u.S. Shores?

The ocean is lawless.

There are no borders at sea.

It's so vast, it's just impossible to police.

Wade: And these subs are designed

to be incredibly hard to spot in open water.

Polakowski: It's a mostly submerged craft that sits just at the waterline,

so it's very difficult to detect along the horizon of the water.

Mckay: On conventional radar, it might not show up

as anything other than another wave on the ocean.

So really, you have to have a visual on it to identify it.

Wade: Few of these vessels have been caught in the act

because many have a built-in failsafe

that helps them disappear without trace.

Mckay: The idea behind the submarines

is that they're pretty easy to dispose of.

If you're about to get caught,

you can scuttle the ship really quickly and get off.

Yeah, it sinks, it's lost.

Where's the evidence?

We don't know how many of these might be lying on the bottom

full of drugs, cash, guns.

Wade: Put where are these subs coming from?

One possibility is the rivers of colombia,

a country that, as I know well,

has many areas that are remote and almost impenetrable.

We have no idea in terms of how many narco subs there have been.

We don't know how many have been successful.

Clarke: The estimates still run to as much as 1/3 or even 1/2

of all the drugs which gets to united states

come via these submarines.

That means it's still a hell of a lot getting through.

Wade: And could the narco sub phenomenon be behind

one of the great unsolved mysteries of the drug world?

It was one of the most infamous drug lords of all time

who first took the narcotics battle under water in the 1990s.

Tuttle: Pablo escobar helped to invent this new method

of delivering cocaine to america.

Polakowski: He was the first one to try to use these narco subs

to transport narcotics in a whole new way.

Wade: Escobar was killed in a shootout in 1993,

but many believe some of his fortune is still hidden away.

Could his missing millions be under the ocean?

I've heard that some of the vast escobar fortune

lies at the bottom in a narco sub.

It's quite possible.

It probably would've been in the form of money

wrapped in plastic.

Wade: Drug cartels have been getting away with it for decades.

But state-of-the-art technology is changing the game.

To catch this sub, the coast guard used

surveillance gear developed for the u.S. Military.

The aircraft which had been most affective so far

is the p-3 orion,

which has a magnetic anomaly detector on its tail.

Wade: The aircraft's magnetic anomaly detector

works in a similar way to a metal detector.

Its sensor can pick out minute variations

in the earth's magnetic field caused by metal objects.

They can detect a magnetic anomaly in the ocean.

That's working on the subs that are built of steel.

So if there's something like a submersible near the surface,

these planes can zero in on them.

Wade: Magnetic detection technology has given the authorities

an edge for now,

but this high-stakes game of hide and seek

is changing all the time.

You move to fiberglass or other non-magnetic materials,

and you can defeat the magnetometers

that may be able to find.

Wade: A fiberglass narco sub

would be almost impossible to detect

with the coast guard's current technology.

It's like a game of underwater cat and mouse.

Clarke: It's going to be a constant battle of technology,

and it's gonna be a constant war of one-upmanship

of who has the most tech.

♪♪

♪♪

wade: We've only discovered a fraction

of what's beneath our oceans.

They hold secrets of our present and our past,

and they rarely give up those secrets easily.

But every now and then,

we stumble upon something truly mystifying.

In 1980, the remnants of an ancient vessel

are discovered beneath the shallow waters of the java sea.

Polakowski: Its timbers are completely rotted away.

This is a seriously old shipwreck.

Wade: Inside are over a 100,000 pieces

of priceless ceramics, many still intact.

Wade: Divers have discovered an ancient shipwreck

full of thousands of pieces of priceless pottery

which have lain undiscovered for centuries.

But where did this ship come from?

And how did it end up at the bottom of the java sea?

Clarke: This shipwreck was special.

It was an old asian design,

and it is full of pottery.

We're talking huge quantities of pottery.

With no ship left, with the wood all gone,

it's really difficult to identify its age.

But from the size of the debris field,

we can estimate that the ship was about 90 feet long

and 25 feet wide.

Wade: Perhaps forensic analysis can tell us more

about this mystery ship.

It's been underwater so long, there's barely anything left.

But the research team catch a lucky break.

You sometimes find organic material,

some of the original cargo, still in them,

which is unbelievable.

In this case, they found a piece of resin

that they use to radiocarbon date the wreck.

Carbon dating allows us to put a time clock

on artifacts that contain carbon.

It turns out that carbon has this isotope

that has a specific decay rate on it,

and if we use that decay rate, we can backtrack time

for how old a specific artifact might be.

Polakowski: Initial analysis has shown that it might've been

a chinese trading vessel from the 13th century.

It's a huge step forward,

but if anything, it only deepens the mystery

because the ship's design and contents

connect it to one of the great mysteries of the ancient world.

For over 4,000 years,

our seas have played a vital role in how we trade.

The oceans have always been the original superhighway,

the original internet.

Wade: But unlike land routes,

they leave very few traces of our trading past.

We know a very small portion

of what was happening on the seas even 800 years ago.

Understanding how the trade flows

and seeing where the trade flows is honestly a way

of charting development of humanity

and how we've grown.

Wade: Can the precious cargo that sat for centuries on the seabed

give us more pieces of the puzzle?

Pottery is actually a very useful tool in dating shipwrecks

because once clay is fired,

it becomes nearly indestructible.

Wade: One of the ceramic pieces carries a maker's mark --

the ancient equivalent of a "made in china" stamp --

and this one is from a chinese province

which only used that name for a short period of time,

which gives them a date range

that could even be in the 12th century.

We're talking about a shipwreck here

that is not long after the age of the vikings.

This is an immense find

in the condition that it was in.

Wade: It's a remarkably rare find.

But can a new kind of radiation technology tell us more?

Scientists developed this x-ray gun

that can use x-ray beams

to detect the chemical composition of the ceramics.

We can look at the composition of the materials

that makes up the pot itself,

and we can date that against a database

of soils and clays from around the world

and be able to get an idea of where the pottery was made.

Wade: X-ray analysis of the pottery reveals something remarkable.

The ceramics had come from different places in china,

hundreds of miles apart.

Mckay: So what these x-ray signatures have told us

is that this ship first loaded and porcelain

in fuzhou and then made its way to quanzhou

and loaded another load

before heading down towards indonesia.

Clarke: This is a very big economic undertaking.

This is not a ship doing a single port to single port

because there'd be no way it would carry such a cargo

focused on just one thing

because it wouldn't be economically viable.

And this tells us the trade network

wasn't a series of small bombs

but actually was big

and constant voyages.

Wade: It's the equivalent of a modern cargo ship,

but 800 years ago,

and it had a traveled an incredible distance

when it went down.

The ship sank 2,000 miles

from where it originally unloaded cargo.

In the 12th century, that is a huge distance.

That's like going across the atlantic.

Elliot: It showed us something we didn't know existed,

which is this long-range trading network from china.

This is a huge breakthrough,

something that we didn't know before.

Wade: But the more we discover about this mysterious ship,

the more we realize how much there is still to learn about it

and the world it came from.

Who were these traders in southeast asia

putting these networks together?

Mckay: We may know the age and where this cargo was made.

We don't necessarily know where it was headed

or even where it was loaded,

so there are a lot of questions yet to be answered.

Wade: Some people say never look back,

but I believe it's only by understanding

where we've come from

that we can truly look forward.

There's still so much we don't know

about what lies beneath our vast oceans.

But perhaps the technology of the future

will finally answer some of our remaining questions

about the past.