All language subtitles for Expedition.Unknown.S17E04.en

Poland, September 1st, 1939,
just before dawn.

The streets are quiet,
but that won't last

much longer.

The distant sound of air raid
sirens heralds

a terrifying reality.

Germany is invading,
and World War II

has just begun.

[intense music playing]

[Josh]
In a lightning-fast assault
known as the Blitzkrieg,

Nazi Germany paralyzes
their enemies

through overwhelming force.

In Poland, the destruction
is catastrophic,

with entire cities
laid to waste.

Soon, more than a dozen
other dominoes will fall.

Norway, Denmark,
the Netherlands,

Belgium, France.

Standing in the way
of Nazi domination

is Great Britain,
but German U-boats threaten

to bring the island nation
to her knees.

[loud explosion]

[Josh] Germany's submarines
were the single

most feared weapons in
the beginning of World War II,

using their stealth and up
to 14 torpedoes each

to hunt in feared wolf packs
and obliterate British vessels,

crippling their supply lines.

And the Nazis dream of making
their subs even deadlier.

Enter German rocket engineer
Hellmuth Walter

and a game-changing U-boat
that could spell Nazi victory.

The top-secret V-80 is
a one-of-a-kind prototype,

a revolutionary rocket-fueled
vessel that reaches

unprecedented speeds
and stays below the surface

longer than any other submarine.

If U-boats boasting
V-80 technology are

launched in time,
the United Kingdom will fall

with Nazi banners flying
over London.

Thankfully, our epic invasion
on D-Day spells

the beginning of the end
for the Third Reich.

And as the victorious Allies
liberate Europe, the Nazis hide

their cutting-edge technology
by sinking the V-80,

sending this game-changing sub
to the depths,

never to be seen again.

Eighty years later,
the legendary V-80 is

still lost.

Now a team of Polish explorers
is using modern

sonar technology and
declassified World War II files

to lead an all-out hunt
for the missing Nazi super-sub.

So damn the torpedoes and set
a course for the icy waters

of the Baltic Sea on
a daring mission to find

Hitler's secret submarine.

[theme music playing]

[Josh]
The past is all around us.

Oh my God!

It goes on forever!

A world of mystery...

Come on!
Look at that!

-Danger...
-Hang on!

-...and adventure.
-It's just straight down!

I gotta get a new job.

I travel to the far corners
of the Earth to uncover

where legends end...
-Yeah!

We got it!
Yes!

...and history begins.

Whoo-hoo!
Here we go.

I'm Josh Gates, and this is
Expedition Unknown.

[epic music playing]

[Josh]
My search for the V-80
begins in Germany,

in the coastal city
of Bremerhaven.

Located at the mouth
of the Weser River here

on the edge of the North Sea,
Bremerhaven was a key base

for the German Navy
or Kriegsmarine,

during World War II.

It served as a hub
of U-boat operations,

producing and repairing subs
that terrorized Allied ships

crossing the Atlantic.

The Battle of the Atlantic was
World War II's longest

continuous military campaign,
starting in 1939 and spanning

the entire duration of the war
until victory in Europe

in 1945.

Under the leadership
of Nazi arch-villain

Admiral Karl Dönitz, U-boats are
ordered to hunt

Allied ships with abandon,

destroying them faster
than they can be built.

He even instructs U-boats
to not rescue survivors at sea.

The campaign brings Britain
to the brink.

But German engineers
like Hellmuth Walter

toil in the shadows to build
an even more terrifying sub.

And he did.

Not far from this shoreline,
Walter designed the V-80,

a lethal German U-boat
that would change

submarines forever.

To get debriefed on the V-80
and how it nearly became

an unstoppable
Nazi super weapon,

I'm meeting
with historian Heiko Mross

aboard a real German U-boat,

the imposing Wilhelm Bauer.

-Heiko!
-[Heiko] Josh!

-Hi.
-[Heiko] Hello.

-Nice to meet you.
-Yeah, how are you doing?

Oh, this is amazing.
Look at this!

This is my first time standing
on top of a U-boat.

This is an astounding piece
of technology.

Any chance that this is
the V-80?

This is not V-80.

Oh, I was gonna say, my mission
would be be over,

it'd be so simple.
-This is a submarine

Type 21 and the last
Type 21 in the world.

This is the most advanced
submarine of Second World War

from Germany, and it could not
be possible without V-80.

U-boats were a huge part
of World War II,

and I think a lot of people
probably assume

that their primary targets
were military ships,

but that's not the case.
-That's not the case.

The primary target was
merchant vessels.

[Josh]
Merchant vessels are critical
to supplying the island nation

of Great Britain
and her citizens.

Nazi Admiral Dönitz's strategy,
known as a tonnage war,

is simple enough.

Sink as many Allied supplies
as possible

and starve Britain
into surrender.

Every month during the war,
U-boats send more

than half a million tons
of food, raw materials

and military resources
to the bottom of the Atlantic.

Germany had how many U-boats
during the war?

-We had about 1,100 U-boats.
-1,100.

And a lot more
than the Allies, right?

It was three-to-one.

But the Germans are not
resting on their laurels.

No, no.

And that brings us
to Hellmuth Walter

and to the V-80.

So who is Walter?

[Heiko speaking]

[Josh]
A cutting-edge German engineer
and inventor, Walter developed

liquid-fueled engines that ran
on hydrogen peroxide,

a powerful, albeit volatile,
fuel source.

His designs powered
the Messerschmitt Komet,

the first operational
rocket-powered fighter

in history.

He applied this same technology
to German U-boat development.

The V-80 submarine is
a one of a kind, right?

[Heiko speaking]

[Josh] Previous submarines had
a bulbous cigar shape,

but the V -0 is built
like a shark,

with a streamlined hull
that slices through the water

and a distinctive conning tower
that would rise

above the surface
like a dorsal fin.

-So how fast could the V-80 go?
-The V-80 could go 28 knots.

20 knots, that's like 33 miles
an hour -- that's fast.

And how fast did U-boats go
before that?

Um, about 8 knots.

So this thing was
almost four times as fast

as other U-boats.
-Exactly.

[Josh] But its shape isn't
the only game changer.

Previous U-boats operated
mainly at the surface.

Once submerged, they had less
than 100 miles of range

before they had to return
topside to run diesel engines

in the fresh air
and recharge their batteries.

And this is a problem, right?

Because when a sub comes
to the surface,

it's very vulnerable.

Three out of every four dies?

-Yes, right.
-Wow, that's insane.

To keep the sub out
of Allied crosshairs,

Walter uses hydrogen peroxide

to create a closed-cycle
turbine engine.

Burning diesel fuel
requires oxygen.

But instead of returning
to the surface to get it,

the decomposition
of hydrogen peroxide

creates oxygen underwater, which
means the sub can stay submerged

and undetected for far longer.

Wow.
Terrifying.

-Does the V-80 ever see combat?
-Not at all.

It was a prototype.

It was a very small prototype,
about 72 feet long

with about a crew of four
to five members.

-Want to take a look inside?
-Inside the sub?

-Inside the sub.
-Oh, I would love to.

-Yeah.
-Please, lead on.

We descend into the heart
of the Type 21 U-boat,

the Nazis' most advanced
killing machine

inspired by the V-80.

♪♪

Wow.

[chuckles]
OK, this is crazy.

Welcome aboard
a German submarine,

but don't touch anything.
-This dive button?

-[Heiko chuckles] No.
-[Josh] No? OK.

So this is like
an engineering marvel.

This was really the first
modern submarine in the world.

Imagine if the innovations
of the V-80 were

adopted earlier and subs
like this made it

into the water sooner.

The war might have been
very different.

It might have totally
changed the war.

All right, show me around,
will you?

[Heiko] Come on.

OK, watch your head, everybody.

Heiko shows off 1945's state
of the art, from stem to stern.

It borrows the V-80 shape,
but not its propulsion system.

So this couldn't go as fast
or stay under as long

as its prototype forebear.

Yeah, Josh, we're here
in the torpedo compartment.

Here are the torpedo tubes.
We're in the front of the boat.

Incredible.

The design of this is
just remarkable.

And this brings us back
to the V-80, which inspired

so much of this.
-Yeah.

How significant would it be
to find the V-80?

The V-80 is a missing link
in the evolution

of the modern submarines.
Finding it would be huge.

So the big question,
where is the V-80?

I don't know.
Nobody knows.

It's a mystery.

So this is today part
of Poland, this area?

-Yes, that's right.
-[Josh] OK.

And do we know
why it disappeared?

[Josh] Only a few days
before Germany's surrender,

on May 8, 1945,
with Soviet forces closing in

on Berlin, Admiral Dönitz
launches Operation Rainbow.

U-boat crews are instructed
to scuttle, or sink,

their own subs to keep
their cutting-edge technology

from falling into enemy hands.

And we think this is
what happened with V-80

in the Baltic Sea.

Well, if I'm gonna find
V-80, I need to go

to where she sank.
So off to Poland.

-Off to Poland.
-Thank you so much.

Good luck.

Roughly 400 miles east
of Bremerhaven is

Gdansk, Poland,
a vibrant port town

with a complicated history.

In 1939, Gdansk was
the free city of Danzig,

a politically autonomous
region created

by the Treaty of Versailles
after World War I.

Governed by the League
of Nations,

the city's population was
primarily German, so Hitler made

recapturing Danzig a pretext
for invading Poland.

Chasing down Nazi submarines
means peeling back the layers

of history, like at this
derelict factory,

which looks like a film set
from a dystopian thriller.

At the height of World War II,
this place churned out fleets

of deadly U-boats.

But 80 years later, it now
serves a different purpose.

♪♪

Welcome to Food Hall Montownia,
where the only submarines

you'll find today
are sandwiches.

These industrial cranes once
serviced the Nazi U-boat fleet.

Today, we'll need them
to carry me out of here.

Basically, it's Hitler's
worst nightmare,

a multicultural melting pot
with dozens of restaurants

and bars featuring cuisine
from all over the world.

If the Nazis had prevailed,
I doubt I'd be eating

an American cheeseburger,
Mexican nachos,

or a Greek gyro.

So eat your heart out, Adolf,
and here's to the heroes

that won the war.

Following in the trail
of the V-80,

I grabbed some wheels and head
20 miles up the coast.

It's just above freezing,
and all around me are

the equally frigid waters
of the Baltic Sea,

famous for its harsh and
turbulent winter conditions.

So when the Nazis took Poland,
they turned this part

of the Baltic Sea
into an experimental test site

for the Navy.

It's where many ships were
developed and repaired,

including U-boats.

After setting its blistering
33-mile-per-hour speed record,

V-80 was stationed here
for further testing,

and the explorer I'm meeting
believes it was scuttled nearby.

At a marina on Europe's
longest wooden pier,

Jacek Dzienisiuk is ready
to embark on a mission

to locate the legendary U-boat.

Josh.

-Nice to meet you.
-Nice to meet you, too.

-OK, so, the Baltic Sea.
-Exactly.

Now, my understanding is
we have a lot of shipwrecks

out here?
-Yeah, there are thousands.

Thousands known
and thousands unknown.

-[Josh] Thousands of them?
-Thousands of them.

The Baltic's graveyard is full
of merchant and military ships

intended to supply Britain
to the West

and their Soviet allies
who were fighting the Germans

to the East.

And there's one unknown
that I know we're both

very interested in, V-80.
-Exactly.

Safe to say that somewhere
out there is V-80?

-Yeah, that's correct.
-She's here.

Absolutely.

You think you've got something?

Yeah, recently I located
a target that looks promising.

You think it could be V-80?

Yeah, the size of it
just looks right.

[Josh]
On a recent scanning mission,
Jacek flagged several

uncharted anomalies
on his boat's sonar.

But before he could record
precise coordinates

and take a closer pass,
he was driven off the water

by the Baltic Sea's notoriously
stormy and dangerous weather.

-And have you dived on it?
-[Jacek] Not yet.

I have to wait
for the right weather.

-And recently, it was very bad.
-OK.

Doesn't look so bad now.

[Jacek] Yeah, that's correct,
but it can change in a minute.

-And the water is very cold.
-Uh-huh.

-It looks cold.
-But if you you dare...

-To find V-80?
-Yeah.

-[Josh] I dare.
-[chuckles] Well, let's go then.

Come on.

We load onto the boat
and head out to sea,

accompanied by Jacek's
research partner,

military historian
Zbigniew Okuniewski.

The water beneath us is
literally freezing,

and somewhere ahead is a sunken
sub with missing Nazi tech

that almost altered
the fate of the world.

We motor a few miles
off the coast, and then I spot

something ominous
on the horizon.

What is that?

This is a Nazi secret torpedo
testing facility

from Second World War.

Sorry, that's a secret
Nazi torpedo base?

[epic music fades out]

[epic music playing]

Sorry, that's a secret
Nazi torpedo base?

[Jacek] That's correct.

[Josh]
I'm on the freezing waters
of Poland's Gulf of Gdansk,

hunting a prototype submarine
that nearly tipped the war

in Hitler's favor.

This part of the Baltic Sea was
a Nazi stronghold

during World War II,
and this crumbling structure

may be one reason why.

They were testing torpedoes.

They were launching them
from the tubes underwater

and testing the explosives.
-Unbelievable.

Wow.

Look at that, just a piece
of history right there.

This is the Kriegsmarine's
Submarine Arms Research Center.

Torpedoes were tested here,
fired at various targets

across the bay.

Now, more than 80 years later,
these ghostly and decaying ruins

are a clue, telling us
we are in the zone

where the V-80 once patrolled.

Oh, so the U-boats would dock
right in there?

[Jacek] That's correct.

It's like, explosives?

Explosives, weapons,
parts of this building.

Uh, we have to slow down,
you know, to be safe.

[Josh] That's no empty threat.

The curtain of mines
and depth charges

that the Nazis used to protect
these waters was impenetrable.

Even the vaunted Soviet Navy
didn't attempt to venture here

until almost the end of the war.

Once we're clear of the tower,
Jacek's research partner,

Zbigniew, joins us on deck.

Our vessel is equipped
with sonar, which emits

acoustic pulses that echo back
from the ocean floor,

creating a picture
of the seabed.

Jacek previously identified
several anomalies

on the northern edge of the bay,
but weather forced him

back to shore.

Now we need to relocate
those hits by searching

in the same area.

Mowing the lawn,
back and forth, back and forth.

[epic music playing]

[Josh]
Finally, after a few passes,

-Josh, we've got something here.
-Oh!

-Look at this!
-Oh my word!

Can we zoom in on that?

-What the hell is that?
-[Jacek] I look at this.

[Josh] Oh, it is sticking up
off the bottom for sure.

Yeah, that look
really promising.

Right? We can see something
kind of elongated,

and look at that shape.

I mean, it does look
like that, right?

-Yes.
-And it has that teardrop

shape like the V-80.

Yes, exactly.

[Josh] So there's something
sticking up in the center

of the structure too.
-[Zbigniew] Yeah.

-Could be a conning tower.
-Exactly.

-Could be.
-[Josh] Could we be

looking at a submarine?

-That's right.
That's right.
-Could be one.

Even the size of it
looks familiar.

That is a great target,
so we've gotta

mark that for sure.

[Josh]
Jacek's hot lead checks out.

Roughly 72 feet long
with a tower-like structure

rising out of the center,
it's a strong match

for the V-80.

And it's not the only wreck
out here.

-Something there.
-[Jacek] Yeah.

-Something there.
-[Jacek] Yeah, we've got it.

[Josh] Whoa!

That is definitely
a sunken vessel.

-And look at the shape.
-[Josh] That's two targets now.

Which one do you think
we should go for?

We can go for T1.

So let's start with this
target one.

-T1.
-[Jacek] Yeah.

[Josh] We have two sonar hits,
one with a distinctly

submarine shape.

Now comes the hard part,
actually diving

in the Baltic Sea,
where the water temperature is

legitimately freezing.

So, we're going to need
more than just wetsuits

or we'll die from hypothermia.

Little warm right now.

Everything feels good.

Everything's gonna be
fine, right?

We start by donning
thermal layers,

then we slip into
a full thermal suit,

then into a full dry suit.

Outside of that are thick
waterproof booties...

Das Boot.

It's a German submarine.
Doesn't matter.

...a full face mask,
then sealed, gasketed gloves

like you might find
on an astronaut.

Once we're kitted up,
and against my better judgment,

we splash down.

♪♪

[Josh speaking]

Whoa!

[Jacek speaking]

[Josh speaking]

While I'm losing feeling
in my fingers, Zbigniew is

on the surface manning
the radio.

[Josh speaking]

[Zbigniew speaking]

[Josh speaking]

The target sits
at nearly 100 feet,

so our bottom time
will be limited.

If we don't get eyes
on this thing right away,

we may not find it at all.

[Josh and Jacek speaking]

We continue swimming
just above the bottom

until something materializes
out of the gloom.

[Jacek speaking]

[Josh speaking]

[Jacek speaking]

[Josh speaking]

[Jacek speaking]

[Josh speaking]

[Jacek speaking]

[Josh] This appears to be
a merchant ship

with openings in the deck
that lead to cargo holds.

[Josh and Jacek speaking]

[Josh]
The hull is largely intact,
but there are damaged areas,

which indicate it may have been
sunk by enemy forces.

[Josh] Once topside, we try
to stop shivering

and get our core temperature up
while relocating

to the coordinates
of the second target.

This hit also looks
like some kind of vessel.

So before I have time to talk
myself out of getting

back into this ice bath,

we hit the water
to investigate.

Oh!

[Josh] The conditions
have deteriorated,

and our already
limited visibility

is even worse
as we descend.

[Josh and Jacek speaking]

[dramatic music playing]

[Josh and Jacek speaking]

[Josh]
We just found something big
at the bottom

of the icy Baltic Sea,
where the experimental

Nazi U-boat V-80 was scuttled
by the retreating German Navy.

But with limited visibility,
we can only see

portions of the wreck.

[Josh and Jacek speaking]

[Josh]
We know that the V-80 was
sunk on purpose

to keep the revolutionary
Nazi tech

from falling into Allied hands.

But even if they blew it
to bits, we still may be able

to find identifying features.

[Jacek and Josh speaking]

[Josh] During World War II,
both Allied and Nazi forces

placed sea or naval mines
around important harbors

like this one, creating
a defensive barrier

to protect valuable resources.

In this case, perhaps
assets like the V-80.

Carrying up to 1,000 pounds
of explosives,

a direct hit from a mine can
puncture steel-hulled ships

and turn a wooden vessel
into matchsticks.

[Jacek and Josh speaking]

[Josh] In the war, hundreds
of thousands of naval mines

were planted
by minelayer ships.

It is impossible to know
for sure, but it appears

that this minelayer had
a terrible accident,

meeting its fate while deploying
its own deadly payload.

[Josh] But then we see something
that may offer

another lethal clue.

[Jacek and Josh speaking]

[Josh] The white material in
front of me is trinitrotoluene,

otherwise known as TNT.

Designed for anti-submarine
warfare and used by both

Allied and Axis powers.

Depth charges would strike
their targets

with a deadly
hydraulic shockwave.

[Josh] Underwater, 250 pounds
of TNT has a blast radius

of up to 30 feet,
with enough power to pierce

a submarine's plated hull.
-It's still alive.

[Josh]
While the two sonar targets
turn out to be forgotten traces

of the war, we need to do
more digging to home in

on the missing sub.

[Josh] We surface and motor
towards shore.

It's not the first time
I've been told to go to Hell,

but it may be the first time
it was meant literally.

Spelled H-E-single
hockey stick, this "fresh Hel"
["fresh hell"]

sits at the very tip
of the peninsula.

The devilish name may come
from a word in Old Polish

meaning "exposed," and sitting
here at the edge of the world,

that feels accurate.

We drop Zbigniew at the dock
and arrange to meet him

later at the military archives,
where he believes

recently declassified documents
could open up a new search zone.

Meanwhile, Jacek and I walk
together through Hel.

It's colder than I expected.

Ha!
I walked right into that one.

Hel froze over.

Counter to everything
I was taught, Hel is lovely,

today anyway.

Now it's a charming
seaside village.

At the start of World War II,
this infernal moniker was

far more fitting.

The Battle of Hel was
an epic clash.

While much of Poland fell
quickly, the Hel Peninsula

resisted Nazi occupation
for more than a month

in the bloody face
of overwhelming assaults

from air, land, and sea.

Recognizing the strategic
importance of the peninsula,

between 1939 and 1941,
Nazi Germany fortified

this position less than a mile
from the center of town.

Oh, wow.

This looks like a rebel base
from Star Wars.

What was this?

Wow, a gun battery.

So there was a gun
in the middle of this.

[Jacek] Yeah, a huge one.
Biggest in Europe, actually

-The biggest gun in Europe.
-Exactly.

[Josh] Known as the Adolf gun,
the 66-foot-long barrel

could fire a 15-inch diameter,
2,200-pound armor

piercing shell
a staggering 35 miles.

Wow.

Crazy.

Back in Poland's possession,
this artillery battery is now

the Museum of Coastal Defense,

celebrating the country's
naval history.

We're here because Zbigniew
has discovered

top secret World War II
communiques to dial in

our hunt for the V-80.

What have you uncovered?

-[speaking in Polish]
-[translator] My English
is limited,

so I will speak in Polish.

My research team found
classified documents about V-80.

These are secret documents?

[translator]
The information we have is
about Walter himself.

So, Walter, who designed
this cutting-edge sub,

the story is that he scuttles it
to keep it

out of the hands of the Allies.
So, what becomes of Walter?

[translator]
Walter ends up in British hands.

He's captured.

[translator]
This is from the Joint
Intelligence Objective Agency.

It tells us what happened after
Walter was in Allied custody.

[Josh] Once he was captured,
the V-80 mastermind became

a high-value asset
for Operation Paperclip.

After World War II, more
than 1,600 top German scientists

and engineers were brought
to the United States

and put to work
on U.S. military projects

to advanced rocketry,
aviation and nuclear research

during the Cold War.

This is after the war.

They now have Walter
in the States,

and he's unhappy.

He wants to go back to Germany.
Is that what's happened?

[translator] Yes.

And where is he
in the United States?

-New Jersey.
-Oh, New Jersey.

No wonder he wants to leave.

So, they write,
"As you may recall

"from previous discussions,
the British consider

"that Walter is in possession
of information so critical

"as to make it imperative
that he remain

in the United States
or United Kingdom."

And so, does he ever disclose
to them in any of his meetings

and interrogations
what he did with the V-80?

[translator] No.

But in another interrogation
by British intelligence,

someone else does.
-Who?

Heinz Ulrich.

Heinz Ulrich?

Heinz Ulrich was a Nazi
test engineer

and Walter's right hand man.

He served as a crew member
on the V-80 during speed

and depth trials.

And what does Ulrich tell
the interrogators?

[translator] That he scuttled it
outside of Hel Harbor.

So this is huge,
because we now have information

about where V-80 left
from to be scuttled.

Ulrich, in his interrogation,
indicated a military facility

just beyond the main town,
where the U-boats once docked.

[translator] And we now know
the exact harbor.

-Can you show me?
-Yes, of course.

Let's go.
Come on.

Can I get a "Hel, yeah?"

The location of the base
where V-80 was docked

just before she was scuttled is
an Adolf gun sized lead.

[Josh]
The military harbor of Hel.

And where was V-80?

[Josh] This is what?
What is this?

Oh, my God!
That's V-80!

That's the submarine.

[epic music playing]

-That is V-80.
-[Zbigniew] Exactly.

That's the submarine.
So it was docked right here.

-Right here!
-[Zbigniew] Yes.

[Josh] Oh, my word.
That's incredible.

I'm in the surprisingly
quaint town of Hel, Poland,

where explorers Jacek
and Zbigniew are hunting

Hitler's top secret submarine,
the legendary V-80.

This one-of-a-kind prototype
was so ahead of its time,

it changed submarine
warfare forever.

So when they went to sink
this sub, they sailed

out of this harbor
straight out here.

[Zbigniew] Yes.

The engineer, Ulrich,
in his interrogation,

did he say how far
out they went?

-He was back fast.
-[Zbigniew speaking]

So they couldn't have gone
very far.

-Exactly.
-So, this gives us

a really defined search area.

[Jacek speaking]

[Josh] That submarine has to be
right out there.

-Yes.
-Must be.

-Back to sea?
-We have to.

[chuckles] We have to.
Come on, this is amazing.

Let's go.

♪♪

[Josh] Armed with a declassified
intel drawing,

giving us a tight search zone,
we follow in V-80's wake.

To prevent the prototype
from falling into enemy hands,

engineer Heinz Ulrich
scuttled it somewhere nearby,

planting explosives
and sending the V-80

to the literal depths of Hel.

So we may be retracing
the final path of V-80.

[Josh] Oh, they didn't just
open the hatches

and let it fill with water.
They blew a hole in it.

That's a great clue.

And that should have happened
somewhere around here.

-Exactly.
-[Josh] OK,

so we've got a new area to scan.
Let's see if we get lucky.

We motor out
just beyond Hel Harbor.

Based on Ulrich's
interrogation, the V-80

should be closer to shore and
to the east of where we found

the minelayer
and merchant ship.

Jacek activates the sonar
and pilots the boat in a series

of parallel
and overlapping lanes.

Minutes turn into hours
as we pass back and forth,

working our way out
from the mouth of the harbor,

hoping to find a 70-foot-long
sonar anomaly on the bottom.

[Jacek speaking]

[Josh] Bingo.

Really solid target.
What is that?

[Jacek] I don't know what it is.

[Josh] It's cylindrical.

Right?
Long shape, whatever it is.

Something's sticking up
off of it, it looks like.

It's got that teardrop shape,
which we know V-80 had.

That has to be a wreck.

[Jacek]
Yeah, it's absolutely a wreck.

You can see it kind of tapers
down here at the end,

so that's -- that's really good.

That wreck is not marked
on the chart?

[Jacek] Definitely not.
It's absolutely new.

-Nothing here on the map.
-What am I looking at?

Well, you're looking
at a mystery.

Yeah, a mystery.
Should we solve that mystery?

-Yeah, let's do it.
-Come on, let's see what it is.

We bundle up in dry suits
to brave the icy Baltic.

Today's forecast is
the same as yesterday.

Really [bleep] cold.

♪♪

The water temperature is
in the 30s.

Diving without
protective layers,

we would quickly freeze.

[Josh and Jacek speaking]

[Josh]
The bottom is shallow.

Our target sits
at just 30 feet.

What do you see?
What do you see?

[Josh speaking]

[Josh speaking]

[Jacek and Josh speaking]

[Josh speaking]

[Jacek speaking]

[Josh speaking]

[Josh]
It's not the missing U-boat,

but this plane is a major find.

An artifact from the war that
hasn't seen the light of day

in 80 years.

We circle the debris,
searching for clues

that will help
tell us its story.

[Jacek speaking]

[Josh and Jacek speaking]

[Josh] We also notice
black discoloration,

a clear mark of fire.

It seems our mystery plane may
have gone down on a bombing run

before it was able to drop
its deadly payload.

Was this a Polish plane
defending its homeland,

a Nazi bomber attacking it,

or an Allied aircraft
liberating it?

[Josh] With ammunition and gun
at the ready,

it appears the airmen were
trying to defend themselves

from enemy fire.

And as we expand our search,
carefully fanning sand to see

more of the wreck,
a shocking discovery reveals

the stark horror that is war.

[Josh]
In submarine design,
every component can become

a matter of life and death,
including the toilet.

Nazi Captain Karl Adolf Schlitt
learned this lesson

the hard way,
when a simple trip to the head

sank his own submarine.

U-1206 was cruising at
200 feet, eight nautical miles

off the coast of Scotland
when nature called

for Captain Schlitt.

Unfortunately, he opened
the wrong valve on the U-boat's

deep-water
high-pressure toilet,

flooding the battery
compartment with seawater

and kicking off
a chemical reaction

that filled the vessel
with lethal chlorine gas.

When the U-boat surfaced
to clear the air,

the British were waiting.

Instead of suffocating,
the crew was captured

and the submarine got sent
to the depths permanently.

Germany surrendered
just a few weeks later.

Ironically, the embarrassing
incident may have saved

the crew's lives.

[Josh and Jacek speaking]

[Josh] At the bottom
of the Baltic Sea,

near a hotly contested
battleground during
the Second World War,

Jacek and I have discovered
a plane wreck.

While it's not the revolutionary
V-80 U-boat,

it is a significant find,
and a tragic one.

This is a war grave,
the hallowed resting place

of an unknown pilot and gunner.

[Jacek and Josh speaking]

[Josh]
We continue to investigate
the uncharted site,

looking for forensic evidence
to help identify the plane

and tell the story
of these lost soldiers.

[Josh]
Our bottom time is limited,
so we quickly grab our camera

and start capturing
a photo mosaic.

[shutter clicking]

I take hundreds of images,
documenting every square inch,

enough to create an exact
3D digital replica of the wreck

and highlight features
not obvious to the naked eye.

Hopefully, it's enough data
to help us identify the wreck.

[Josh] Whoo!

Incredible.

Just an entire aircraft
down there.

Nobody knows that's there.

-[Jacek] Nobody.
-Nobody.

And it looks like we have
remains down there as well.

-OK.
-[Josh] So, I mean,

this is not just a piece
of lost history,

but there's a personal story
here, too.

-[Josh] Missing in action, yes.
-Yeah.

OK, what will happen now
with this plane?

Yeah, it is a grave,
a war grave.

That's right.
Amazing job.

Really amazing.
Hey, great job.

Thank you so much.

V-80 is still out there,
but this is a lost piece

of history that's lost no more.

[Josh]
The photos come together
like pieces in a puzzle.

The three-bladed propeller,
distinct squared-off cockpit,

and tell-tale Berezin UBT
machine gun

identify this plane
as the Russian

ground attack aircraft
Ilyushin Il-2,

known as the flying tank

for its heavily
armored construction.

The Il-2 was so important
to the Soviets during the war

that Stalin said, "It was
as essential to the Red Army

as air and bread."

The crew of this plane made
the ultimate sacrifice,

meeting their fate
while liberating Poland

from the Nazis.

The Baltic doesn't give up
its secrets easily,

but this mission was
a major win

as we uncovered lost and
important relics from the war.

A missing merchant vessel,
a wrecked minelayer...

[Josh]
...and this historic discovery
of an Il-2 aircraft.

[Josh] The V-80 remains
unaccounted for,

but her legacy is clear.

She was a hallmark
of naval engineering

and the first incarnation
of modern submarines,

which influenced every sub
built after.

But if the technological
advances born

in Hellmuth Walter's
revolutionary U-boat

had evolved slightly quicker,

a cascade of dominoes
might have fallen.

Cut off from supplies,
Britain may have starved,

and the flow of shipments that
the Russian army relied upon

likely would have ceased,
buying just enough time

for the Nazis to develop
atomic weapons.

It's a haunting shadow
of an alternative reality,

where freedom, liberty,
and equality became

words that could only be
whispered in secrecy.

We take for granted
how close we came,

and too often forget
the enormous sacrifices it took

to avoid that terrible fate.