All language subtitles for Secret.Nazi.Bases.S04E01.A.Secret.Canal.1080p.UKTV.WEB-DL.AAC2.0.H.264-RAWR_track3_[eng]

Beneath the densely woven forests
of northern Poland,

a jagged scar etches its way across
the landscape.

50 kilometres of weathered
concrete carves

a path through the waters
of Lake Mamry to

the open plains of the Baltic Sea -

a forgotten canal branded by
a fallen empire.

This imposing structure bears

the ominous signature
of Nazi Germany -

a testament to the imprint they had
on this region.

Preceded by decades
of failed attempts,

a fragmented foundation lay dormant
until Hitler seized

the chance to revive this
waterway into

a monument of totalitarian might.

The Masurian Canal,
once finished,

would be a symphony of steel
and concrete,

bending the waters to
the will of the Reich.

There are thousands of tons
of concrete in this.

It is difficult terrain
to build in.

This was a complete system,
designed to dominate

the waterways of East Prussia.

This will become one of

the largest engineering
projects that

the Nazis will undertake in
East Prussia.

Capable of carrying ships of up
to 240 tons,

this ambitious waterway would link

the secluded Masurian lakes to
the open sea,

forging a vital artery

of commerce through
German-controlled territory.

Though built under
the facade of economic progress,

this relic of Nazi engineering may
harbour a far darker secret.

Why did Hitler want to resurrect
this engineering project?

What potential advantage or benefit
did he see in

an abandoned waterway?

To this day,
there's still speculation as to

the true purpose of this waterway.

Why was its construction kept
a secret?

And in the end,
why was it all just forgotten?

1933, East Prussia,

a lonely German enclave isolated by
foreign borders.

After World War I,
Prussia was divided

and parts of its territory were
given to Poland.

East Prussia became

a territory of Germany
that was non-contiguous.

The only ways to access it from

the rest of Germany were by
land through

the Polish Corridor, or via
the Baltic Sea.

Comprised largely
of agricultural lands

and lush mixed forests,
its northern region also boasts

a rich inland reserve
of freshwater lakes.

The Masurian Lakes District

of northern East Prussia has about
2,000 lakes.

It covers an area of roughly 52,000
square kilometres,

similar in size to
a country like Costa Rica.

It extends eastward from
the lower Vistula River to

the modern day border between Poland

and the Russian exclave
of Kaliningrad.

However, this region finds itself in
a precarious position,

located in an outpost of Germany
that's deeply vulnerable

to external interest.

As the Nazi Party ascends to power,

the Masurian Lakes
and the Greater East Prussian

stronghold take on
new significance.

It is not just a border that
Germany needs to protect,

it is also a buffer zone between
Germany and Russia.

It is territory which can be used

for infrastructural developments
such as factories,

armament factories, that would help
Germany in its war effort.

And then finally it is
geo-strategically important

for Germany for the logistical
movement of its troops.

For any kind of operation
launching into

the Soviet Union,
it's a good staging point.

It's also a good staging point if
they go to war with Poland.

After Hitler comes to power,
the Nazis begin

to transform East Prussia from

agricultural heartland into more
of an industrial area.

Yet to unlock the vast potential
of this wooded region,

an extensive overhaul of
infrastructure would be required -

a web of railways,
roads and robust waterways.

As Nazi planners survey
the East Prussian landscape,

their attention is drawn to
a winding trail

of abandoned concrete beds snaking
through the terrain -

the remnants of the Masurian Canal.

These sprawling foundations were
the beginnings of

the Masurian Canal,

a transportation project that had
broken ground decades earlier.

The plans for this waterway was
to connect

the Masurian Lakes with
the Baltic Sea.

By the dawn of Hitler's reign,

the art of canal engineering was
well-established across Europe.

The Reich's ambitions, however,

would breathe new life into this
age-old technology,

etching a symbol
of their empire into the earth.

Canals are a really important part
of our

transportation infrastructure.

They allow marine traffic to
traverse

a shorter distance between different
bodies of water,

different elevations of water.

It's a very difficult construction
to do,

but it can be very meaningful in
allowing communities

to evolve and flourish,
and it is a critical piece

of infrastructure to drive that
growth.

The first proposals for the Masurian
Canal can be traced back to at least

the 18th century, the golden age of
waterway construction.

During this era,
administrators under King Frederick

the Great of Prussia seek
to establish new channels of trade

and transport across their kingdom

and note the potential
of this expansive lake district.

Between the 17th and 19th centuries,
Europe experienced a canal age,

a period of increase in
the building of these waterways,

because they'd become
the fastest means

for long distance travel
and transport.

By the 19th century,

Europe has an intricate network
of canals that connects

the English Channel with
the Atlantic Ocean,

with the Mediterranean Sea.

Canals really become
the veins through which

the lifeblood of European
progress flows.

This idea, however, would lie
dormant until the mid-19th century,

when the notion resurfaces as
the Allenburger Canal Project,

a 50-kilometre long route capable

of carrying cargo ships into
the heart of the region.

This proposed channel would allow
freighters to navigate

an elevation change
of over 100 metres

from the coast to the interior -

a vertical feat that would require
the incorporation of

a crucial mechanism.

The elevation difference between
the Baltic Sea

and the Masurian Lakes is
111 metres.

That's about the height of Big Ben.

By the end of the 19th century,

canal construction is facing
competition from

the advancements in
steam locomotives.

The canal proposal and the land it
would traverse undergo

a number of changes in
the following years.

As the region is absorbed into
the German Empire,

revisions reflect new priorities,
one of which sees

the initially promising inclined
plane design replaced by

a more conventional yet reliable
lock mechanism.

An inclined plane is simply
a mechanical method

for moving boats between
different elevations.

Using a system of cables
and powerful engines and brakes,

that boat is either raised up or
lowered down the incline.

Lock gates have been used to raise

and lower boats along waterways
for thousands of years,

and the theory behind them is
actually very simple.

If a ship is moving downstream
to enter the lock,

it goes through
the entrance gates where

the lock gates close behind it,

and it is now in
a watertight chamber.

A valve is then opened,

which drains that water inside
the chamber

and lowers the ship.

Once lowered,
the exit gates open

and the ship can sell out
through it,

now at a lower elevation.

And, if it needs to go the other
way,

ie back up,
you just reverse the process.

By the spring of 1911,
after decades of deliberation,

the project finally navigates
the maze of bureaucracy

and emerges with
official authorisation

and a budget of 15 million marks.

The sound of machinery breaks
the silence of

the East Prussian woodlands,

and the vision of this enormous
hydro-course begins

to take physical form.

But, as workers toil to reshape
the terrain,

a distant rumble grows on
the horizon,

one that would soon reverberate
across the continent

and bring construction to
an abrupt halt.

1914, a young Adolf Hitler leaves
the streets of Vienna for

the German city of Munich,

a place pulsating
with nationalistic fervour.

Swept up in the patriotic tide,

Hitler disregards his foreign status

and enlists with the Bavarian Army.

The Great War has begun,

and he eagerly heeds the call
to arms.

Hitler's involvement in
the First World War is

a seminal moment in his life.

Before he enlists in
the Bavarian Army,

he is a failed artist,
he is a man without purpose.

His involvement in the First World
War gives him

purpose for the first time in
his life.

This is the most positive,

formative experience that
Hitler had

in imbibing
German nationalism, patriotism,

fighting alongside other
German soldiers

and developing that sense
of military honour,

it's a very transformative
experience for Hitler.

As Hitler joins
the front line in Belgium,

the German Empire faces
a grave threat from the East.

The Russians have set their sights
on Berlin,

but, before they can march on
the capital,

they first must contend
with their enemy's nearest frontier,

East Prussia.

In this outlying province,
the Masurian Canal sits unfinished

and exposed - a testament of German
engineering,

now vulnerable to the
tides of war.

As the summer of 1914
harrowingly unfolds,

Russian forces surge across
the border

and the tranquil lake district is
transformed into

a deadly battleground.

The province of East Prussia,
on the periphery of Germany,

is actually the only part of

the German Empire itself that saw
direct combat during World War I.

By this time, the Masurian Canal is
already

three years into
construction,

but only a tiny proportion
of earthworks have been completed.

And whilst by today's standards
that speed

of progress might seem
incredibly slow,

you need to understand the
challenges that were presented

by the rugged and remote terrain it
was attempting to cross.

Though the Germans hold their ground
in East Prussia,

their leaders will ultimately

surrender after years
of combat against

a powerful coalition of enemies.

In the war's aftermath,

the defeated Weimar Republic is left
to count its losses.

As the nation struggles
to rebuild from

the ashes of defeat,
work on the Masurian Canal resumes.

However, in just a few years,

the Republic's withering economy
once again brings the project,

along with many others,
to a standstill.

Eventually, this stalled mega
structure will fall

into the hands of a burgeoning
radical

intent on transforming the
nation.

1934, under Hitler's Germany,

labourers are sent in droves to

the forests of East Prussia
to resurrect

the failed Masurian Canal.

And soon an "Arbeitslager",
or labour camp,

is erected to accommodate
the growing pool of local

and conscripted workers.

A sense of urgency lingers in
the air -

Nazi administrators wish to see
the canal completed by

the turn of the decade.

There seems to be
a really aggressive push

to resurrect this canal project.

Why is it that there is such focus
placed on this undertaking?

So there's many different objectives
that could have been at the back

of Hitler's mind.

The one that they probably started
off with, before even

the beginning of World War II,

was to kick-start economic growth
and development.

A decade earlier, the toll of
Germany's surrender

had severely deteriorated
the economy.

Runaway inflation had plummeted
the mark to absurd lows,

with citizens requiring wheelbarrows
of money to buy

a single loaf of bread.

Following their reluctant signing of
the Treaty of Versailles,

effectively ending the war,

the Weimar Republic was broke
and defenceless.

The Treaty of Versailles is

the peace treaty that
Germany is forced

to sign when it loses
the First World War.

It sets out a number of terms
and conditions,

and these include
the loss of territory,

the loss of their army,

which has to be limited to a very
restricted number of troops

and cannot be developed
significantly.

Germany is required to pay
significant

reparations that end up
crippling its economy.

The "stab in the back" myth is this
idea that Germany didn't actually

lose the war on the battlefields,

that it was stabbed in
the back by a group of Jews,

socialists and pacifists.

And it is a myth that is
perpetrated by

the German high command
to save face -

the idea that Germany didn't lose
the war.

It is a total myth,
because Germany did lose the war.

There's absolutely no doubt
about that -

Germany signed the Armistice
because it couldn't keep fighting.

Hitler seizes the simmering
resentment like a weapon,

ascending the public stage as
a leading member of

the nationalist Nazi movement.

His fiery call for a New German
Order

herds thousands to his support.

Although the Nazi Party forms in
the early 1920s,

it isn't until the late 1920s,
and in particular when

the Great Depression really sets in
in Germany after 1929,

that we see a significant rise in

the popularity of this
political party.

The party's radical platform finds
growing appeal among

a populace that's disillusioned by
the failures of

the Weimar Republic.

Soon, the Nazis become
the largest party in the Reichstag,

and Adolf Hitler cements his seat as
the absolute dictator of Germany.

His initial ambition is
to rebuild Germany economically,

and for him, the way to do that was
to create jobs.

How do you create jobs? You launch a
whole lot of

infrastructure projects
all over Germany,

and you try to start building up
the army,

go on the defensive,

protect the German economy in order
to rebuild the country.

Under Hitler's iron-fisted rule,
every corner of

the Reich sees dramatic
transformation,

as a series of aggressive policies

and infrastructure projects are
hastily set in motion.

In the enclave of East Prussia,
change is already well under way.

At the orders of the provincial Nazi
leader, Erich Koch,

agricultural lands once tilled by
independent farmers

is collectivised and the region
moves towards

mass industrialisation.

Erich Koch is the regional leader

of East Prussia when
Hitler takes power.

Erich Koch uses these emergency
relief funds

to really establish industry in
East Prussia.

Koch is quick to tout his success,
asserting that his policies have

eradicated unemployment in
East Prussia -

a feat that garners widespread
acclaim throughout the Reich.

Koch proclaimed that he had

eradicated unemployment in
East Prussia,

and this became a powerful tool of
Nazi propaganda -

Hitler would tout that.

And by claiming to have eradicated
unemployment in East Prussia,

Koch became famous -
he was the recipient

of widespread acclaim throughout
Nazi Germany.

Soon the unfinished Masurian Canal,

previously left abandoned to
the forest floor,

resurfaces yet again -

the perfect foundation for
a network of maritime traffic.

In 1934, Hitler's first year as
Fuhrer,

his party approves
the continuation

of this crucial bridge
to the Baltic,

with a commitment
of 19.5 million Reichsmarks.

Connecting the Masurian Lakes to
the Baltic Sea,

opens up a new artery of trade
and transport for the Germans.

But, maybe there were other reasons,
beyond economic reasons,

that Hitler wanted
to complete this canal.

From what we know about
Hitler today,

it's very likely there was
an ulterior,

perhaps darker motive behind
this project.

In the bug-infested backwoods of
the Masurian Lakes,

labourers rush to advance

the Masurian Canal's long-awaited 50
kilometre span from Lake Mamry to

the Lyna River,

where vessels could then navigate
onwards to the Baltic Sea.

The timeline from 1934

to 1941 that Hitler imposed on

the project to be completed by is
incredibly ambitious.

It would take years of planning

and design to make this work -
it's a giant project.

Though having sat dormant for a
decade,

its unfinished contours had slowly
been reclaimed by the elements.

Years of neglect had taken
their toll,

and, before Nazi shovels can carve
new ground,

the existing foundation
must be reassessed.

The first step of any construction
project is actually

to build infrastructure just
to get to the site,

let alone making sure that you have
materials available on site to build

the things you want to do.

We're talking about excavators,

the potential blasting if they hit
rock.

That is just an
incredible undertaking.

To address a project of this scale,
planners pull hands from

the consortium that would become
known as Organisation Todt.

Organisation Todt is
an extensive civilian

and military labour force.

This organisation is responsible
for building roads,

railways, factories, and
fortifications across the Reich.

Organisation Todt will be the
largest workforce in Germany.

Eventually, they'll have over a
million,

I don't want to say employees

because they include slave labour,
conscripted labour,

foreign labour and prisoners of
war,

but they will have over

a million people slaving
for them indeed.

The task ahead is monumental
and the specifications daunting -

a 2.5 metre deep gash in

the earth that weaves over 50
kilometres through

a dynamic landscape.

At its lowest point, the canal bed
would span 13 metres wide.

And, once eventually filled
with water,

the breadth from bank to bank would
stretch 23 metres across.

The canal itself would then be
accompanied by hundreds

of subordinate structures such
as siphons,

tunnels, bridges,
outbuildings, reservoirs,

and even small passages
for local wildlife.

And the challenges extend beyond
sheer size.

The Masurian landscape is
a mosaic of rolling hills

and marshy lowlands.

Cutting through this unpredictable

terrain demands
constant adjustments.

To smooth its course,

the Nazis create massive embankments
along the spine of the canal.

Certain sections of
a canal construction will need

the use of embankments,
which are essentially lengths

of compounded raised earth that
are used

to avoid any significant height
fluctuation for the waterway.

And some of the embankments on

the Masurian waterway measured up
to 15 metres high.

That's a lot of earth to build up.

From the sprawling earthwork arises

a chain of ten reinforced
concrete locks,

massive mechanisms used to drop

and elevate ships along their route
to and from sea.

There are ten locks across
this canal,

and they categorise those locks
based on

the elevation change from eight
metres of elevation change all

the way upwards to 30 metres -
that's a really big distance.

The manual capabilities

of these locks is crucial in case
there is some kind

of malfunction or any kind
of power outage.

One end of the canal touches
the edge of Lake Mamry,

in the heart of
the Masurian Lakelands.

Here, vessels will pass through
the grandest feature of

the entire system.

The scale of the Lesniewo Upper Lock
is a true sight to behold.

It is the king of this canal.

The length of its chamber is
a whopping 46 metres.

Working in tandem
with its sister lock,

the Lesniewo Lower Lock,

it can lift or lower ships
33 metres.

That's about the height of
a ten storey building.

Inside the lock's chamber,

the Nazis also built
a labyrinth of rooms to house

the mechanism for operating
the lock.

Now known as the Lesniewo
Upper Lock,

Schleusen Furstenau is

the crown jewel
of this ambitious project,

a showpiece of the Nazi regime,

its towering concrete facade,

emblazoned with the Imperial Eagle,
the Reichsadler

and the swastika of
the Third Reich's coat of arms.

The financial investment
of this canal is staggering.

Building a single kilometre of

the canal costs 800,000 Reichsmarks,

which is the equivalent
of $7 million today.

In fact, it is second only to
the development of

the autobahn in East Prussia.

This canal has sort of had
a stop/go history,

so it seems now with
the Nazis in power,

that for the first time, the canal
will actually be finished.

For some time,

it seems the Nazi promise
of new infrastructure

and economic rebirth in East Prussia
is coming to fruition.

Between 1933 and 1936,

employment in the construction
industry across

the Reich nearly triples.

The Masurian Canal is poised to be
a testament of progress.

But a dark undercurrent runs beneath
the surface.

As the decade lingers on,
Hitler's true ambitions,

and perhaps the ultimate purpose

of this inland waterway will soon
be revealed.

This canal doesn't feed any
big city,

so what is it about this region that
lures the intrigue

and the interest of
the Nazi leadership?

For all its power and scale,
the construction of

the Masurian Canal is shrouded
in secrecy.

Only high ranking loyalists are
privy to

the true extent of the plans,

leaving many to wonder about

the real purpose behind this
massive undertaking.

In the late 1930s,

the canal does not appear on
any maps.

You don't want it advertised, or
certainly

identified where exactly it is.

The closer we get to the War,

the more it seems this canal is
being hidden.

But, the completion of
the canal may be far more than

an economic endeavour -

perhaps this waterway is

a key piece of Hitler's grand
political puzzle.

Could this canal be used
to serve areas that are being used

for clandestine
military operations?

Is it possible that this remote,

isolated outpost is in fact
a launchpad

for Hitler's vision for
"Lebensraum"?

Lebensraum is a very old concept in
German history -

"living space".

It entails this idea that

the German people should take over
essentially Eastern Europe,

all the way to the Ural mountains
which divide Russian Asia

from European Russia.

Beneath the shadows, Hitler is
rolling out

plans that brazenly defy
the punitive Treaty of Versailles.

Under the guise of performing
routine maintenance

on his existing fleet,
he secretly approves

the expansion of the Navy,

projecting the construction
of battleships,

destroyers, and submarines,

all in direct violation of
the Treaty's terms.

His aim is clear,
to transform his allowable,

small defensive force into

a formidable military capable
of offensive action.

This marks the first step towards
building the fearsome Wehrmacht.

Hitler was always looking for ways

to re-militarize in defiance of
the terms of

the Treaty of Versailles

and take steps to create
a powerful German military,

the Wehrmacht, Germany's unified
military made up of the Heer

or the Army, the Kriegsmarine,
the Navy,

and the Luftwaffe, the Air Force.

Hitler is essentially mobilising

the entire population of Germany
to be on a war condition.

September 1st, 1939,

the fragile peace in
Europe abruptly implodes as

German forces unleash "Fall Weiss",

a devastating blitzkrieg across
the Polish border.

As Luftwaffe planes darken
the skies over Warsaw

and Panzer units thunder into
the country,

Poland finds itself surrounded by
Hitler's relentless war machine.

Within days, their defences crumble
under the onslaught

and the world watches in horror as

the once sovereign nation is
torn apart.

This signals the beginning of

the deadliest conflict in
human history -

the Second World War has begun.

Hitler had been preparing the
country for greatness, essentially.

Ever since he'd taken over power,
he was trying to rebuild Germany

and help Germany regain its foothold
in Europe.

As Hitler plunges Europe into
the Second World War,

every single strategic resource that
Germany has becomes essential

for its war machine.

And this could potentially extend to
the Masurian Canal.

Yet, as the conflict spreads across
the continent,

priorities shift dramatically.

All attention pivots to
the immediate exigencies of warfare.

In the remote reaches of Masuria,

work on the canal is consequently
paused, as resources

and labour are redirected to
a more pressing need in

the Eastern Corridor.

It makes sense that
the workers who were building

the Masurian Canal at
the time were redirected

to start building the Wolf's Lair,

because that was
a military headquarters,

and it was extremely essential
for Hitler,

because that's where
the entire war plan was created.

And it needed to be in
a place that was well-protected,

in a place that was well-hidden,
and a place that was well-supplied.

Around 20 kilometres southwest
of Lake Mamry,

nestled in the wilds of Gierloz,

a grand undertaking is set
to outpace the canal.

Utilising the natural barrier of
the Masurian Lakes,

builders hurriedly work
at constructing

a 6.5 square kilometre compound
to house

the eastern headquarters of
the Fuhrer himself.

Aptly named Wolfsschanze,
or the Wolf's Lair,

this will become the heavily
fortified nerve centre from which

Hitler will orchestrate all military
operations in the eastern arena.

All these resources that are being
deployed to the canal,

suddenly those resources are now cut
back to build the Wolf's Lair.

This complex of bunkers
that is enormous,

that is as big of
an engineering enterprise as,

you know, a few miles of canal.

Additional subordinate headquarters
associated with

the Wolf's Lair are dispersed
throughout the region.

The largest of these satellite
compounds sits on

the western bank of Lake Mamry.

Designed as a base for the
Wehrmacht's Supreme Army Command,

the Oberkommando Des Heeres.

Construction of the sprawling
settlement known as OKH Mauerwald

is entrusted to the Organisation
Todt workforce

that has previously carved the bulk
of the Masurian Canal.

Within a single year,
they're tasked with erecting one of

the most impressive military bases

for Chief Staff that
East Prussia has ever seen.

Mauerwald translates
to "Wall Forest"

and is essentially what it
sounds like -

it is a wall of concrete in
the middle of the forest.

This is a place that has its own
power grid,

drainage system,
communications network,

and even a hospital.

And, at its busiest time during
the war,

there are over 1,500 officers
living and working here.

Thousands of labourers are
employed over

the next four years
to build this massive complex.

A common practice employed by

the Nazis in their massive
construction projects was

to shuffle workers out.

And this was in
the interest of security -

there wasn't anyone who had
worked on

a project from beginning to end
and knew its full scope

and all of its dimensions.

Both Mauerwald

and the Wolfsschanze were also
camouflaged as chemical plants.

Nobody realised that there was
kind of

a military significance to
the Mauerwald.

The operations at Mauerwald are
shrouded in protection.

The site itself is
a fortress of secrets.

Access to the compound is
strictly controlled,

connected to Wolfsschanze only via
a single rail line.

Interestingly,
Mauerwald is located along

the southern edge of
the Masurian Canal.

Situating this major military base
so close to

the canal does suggest that
the purpose of

the canal from day one was not
just economic.

And obviously, in war, control of
the waterways is paramount.

The Germans build

a number of these fortified command
posts in East Prussia,

because they are planning
an invasion of Eastern Europe.

In August 1939,

Hitler and Stalin sign
a non-aggression pact.

This gives Hitler the green light
to start World War II.

It's also very interesting,

because what it means is between
the invasion of Poland

and Operation Barbarossa,
Nazi Germany and

the Soviet Union are
essentially allies.

It means that after Hitler's
conquered Poland, he knows he has

a friendly power on his
eastern border,

so he can turn his full attention to
the West.

Hitler sets his sights on knocking
Britain out of the war,

and he tries to do this through
the Battle of Britain.

He fails -
Britain wins the Battle of Britain.

So, then Hitler turns his attention
to his ultimate goal,

which is the defeat of
the Soviet Union.

As the war brutally treads on,
steel is forged

and machines take shape across
the Reich.

Envisioning an ocean fleet capable
of maritime dominance,

Hitler calls for
the widespread production of

the nation's most ferocious naval
weapon, the U-boat.

Arguably, the U-boat is the German's
most powerful naval

weapon of the 20th century.

Initially used in
the First World War,

these vessels could dive to
a depth of around 50 metres

and had a range
of 40,000 kilometres.

Because the U-boat can travel long
distances without being detected,

it allows the Germans to be able
to circumvent Allied blockades.

Lurking beneath the waves of
the Atlantic,

this silent predator gains notoriety
for its ability

to strike from the depths
without warning,

leaving a trail
of destruction in its wake.

In the First World War alone,

German and Austrian U-boats sank
around 8,000 Allied merchant

and warships many times their size,
claiming the lives of tens

of thousands of sailors in
the process.

Submersible vessels experience
an incredible amount

of pressure as they dive deeper into
the water.

The U-boat design employed

a new alloy that was stronger than
previous steels

and allowed them to go deeper

and to resist that pressure
and to be safe.

During the Second World War,

the Nazis continuously developed
the design of the U-boat

and at one point incorporating
the G7e electric torpedo.

Whilst it sacrificed some speed

and range compared
to its steam powered counterpart,

it no longer had the telltale stream
of bubbles behind it,

which made it much more difficult
to detect.

At the start of
the Second World War,

the Kriegsmarine has just 46
operational U-boats,

but by 1941 that number increases
to 365.

Producing U-boats is
very challenging.

Not only are they
a large machine that takes

a lot of work to actually
build them,

the U-boat construction is being
targeted by the Allies.

And the reason for that is
because they are one of

the biggest threats that
the Allies face.

The Battle of the Atlantic is
a life or death struggle

for the continued ability of Britain
to resist against the Nazis.

If you were looking to build up
the capacity

of your Navy, away from any external
prying eyes,

there's probably no better place
to do it than away from

the coast in this remote
forestland.

And, through the canal,

with the potential
to have access to the open water,

it's almost the perfect place
to set up a secret shipyard.

Some say the canal may be intended
to service

a secretive U-boat shipyard that

allows easy access from
German territory to

the Baltic Sea, where vessels could
then navigate onwards

to cause devastation in
the Atlantic.

The canal is wide at certain areas,

and that's a critical design aspect.

These widened areas allow for
a larger turn radius of up

to 40 metres - that is the turn
radius of a smaller U-boat.

There is a big issue
with that idea -

the canal is only 2.3
metres deep,

while the draft of
a U-boat is over four metres.

Putting it simply, a U-boat could
not sail through that canal.

However, as the Kriegsmarine scales
back manufacturing from massive

shipyards to smaller factories that
produce prefabricated parts,

the feasibility of work along
the canal remains.

The Allied bombing campaign
really undermines

Germany's war economy,

as it forces them
to make radical changes

to how they're producing
war machines.

They suddenly now have
to build them in

heavily-fortified factories
and then

bring them all together
for assembly.

Prefabricated parts can be
barged out, you know,

hide the prefabricated
factory outside

of occupied Prussia.

If one gets bombed out,

they can turn to another factory
for the parts.

Could Mauerwald have served
a dual purpose,

not only as a command centre,

but also a cog in the machine of
the Nazi war effort?

The function of most of the
buildings at Mauerwald

are known to us today, but some
still retain an air of mystery.

Buildings 11 and 12 are
a little bit suspicious.

They're really big -
they're 13 metres by 21 metres,

and they were purported to be
a boiler room and a power plant.

These buildings are way bigger than
what would be needed

for those utilities.

It might have been built
for something else in mind.

Was there a secret shipyard
for building U-boats,

or for making components
for U-boats in

the Masurian Canal? We don't know.

But if a secret U-boat shipyard or
a factory did exist,

where along this canal could it
have been?

As the war rages on,

work on the Masurian waterway is
slowed to

a near halt by 1941.

But this vast structure will
soon find

a new purpose not as
a transport route,

but as a strategic barricade in yet
another deadly offensive.

June 22nd, 1941,

more than three million Nazi
soldiers are quietly amassed along

the 2,900 kilometre border between
the Reich

and the Soviet Union.

At the utterance of
a simple command,

they blazed forward in
a brutally deceitful attack -

Operation Barbarossa.

When Hitler then defies
the non-aggression pact

and opens up the Eastern Front
with Operation Barbarossa,

I think his calculation was that
this would stunt

the Russians
and would give Hitler

the edge going into
the war against the Russians.

Backed by thousands of tanks
and aircraft,

the Germans steam-roll east,

swallowing vast swathes of land,

crushing the ill-prepared resistance

and unleashing a conflict that would
ultimately decide

the Second World War.

Operation Barbarossa is arguably

the biggest strategic blunder that
Hitler makes during

the Second World War.

He hasn't actually finished his war
in the West,

because Britain still exists.

And, so what he does is he condemns
Germany to fight

a war on two fronts.

OKH, German High Command,
becomes one of

the most important units during
the planning of this operation.

The location of the Wolf's Lair
and Mauerwald allows Hitler

and his generals to closely monitor
what's happening

in their fight against
the Soviet Union.

Operation Barbarossa ushers in
a new chapter of

the war, as Nazi forces relentlessly
push into

the Russian countryside,
their sights set on Moscow.

Yet despite their
meticulous preparations,

the invasion is a gamble.

And, in December of 1941,

after months of successful
German advances,

the Red Army unexpectedly turns
the tide,

forcing the Wehrmacht into
a steady retreat.

Though construction had
already stopped,

the Masurian Canal was around
90% complete

and virtually filled with water.

As the Germans retreat

and the Soviets advance into
Germany proper,

the Germans are forced
to turn everything

and anything into a defensive line.

And so the Masurian Canal becomes
part of that defence.

And what you see is
the canal is being used by

the Germans to try and halt the
unstoppable Soviet onslaught.

And as part of that, they're
actually destroying parts

of the canal, including bridges,
to try and do anything

to slow down the Red
Army's advance.

But this hastily cobbled
defensive line,

an act of desperation in
the face of defeat,

is not nearly enough
to stave off the oncoming attack.

A tide of Soviet steel
and determination pours westward,

fuelled by the blood of millions
and the support of Allied resources.

City after city falls,

each bringing the roar
of Russian tanks closer to

the heart of the Third Reich.

By May 1945,
the Soviets seized Berlin,

and the war in Europe is finally
brought to an end.

At the end of the war,

Josef Stalin meets
with American President Harry Truman

and British Prime Minister Winston
Churchill to decide

the fate of Germany.

They sign the Potsdam Treaty,

which divides Germany between
the superpowers.

East Prussia is divided into
two parts.

The majority is annexed by Poland,

and the remainder goes to
the Soviet Union.

Poland and the Soviet Union find
themselves in possession of

a regime's scattered remains across
East Prussia.

The two powers divide the course of

the unfinished Masurian Canal
between them.

Roughly 20 kilometres fall under
Polish control,

while the remaining 30 kilometres
becomes Soviet territory

with five locks in each section.

However, this partition does little
to breathe new life into

the long neglected project.

Neither Poland nor
the USSR possesses the resources or

the will to complete
the canal's construction.

The grand vision of
a navigable waterway connecting

the Masurian Lakes to
the Baltic Sea,

and the secrets it once contained
fades into obscurity,

overtaken by the pressing demands of
the postwar era.

The fact that the canal does not get
much use during

the war means that perhaps it
did not meet its full

strategic potential.

Today, the canal is in
a state of disrepair and decay.

A lot of the elements were
either destroyed,

deteriorated, filled in.

It is not a functional structure.

Much of the equipment from
the lock gates has been looted,

rendering them completely
inoperable.

There's still a lock that has
a kind of a shadow of

the old eagle Nazi symbol,

leaving this kind of imprint
of its Nazi history to this day.

Seeing this intimidating Nazi symbol
on this imposing feat

of engineering would really
drive home

to anyone passing through,

this regime has built
something impressive -

they are leaving their mark on
the landscape,

they are a force to be
reckoned with.

What's interesting here is,
as they were taking off

the actual emblem,
it fell into the water.

So, it poses this
interesting question,

is it actually still in the canal?

Though seemingly forgotten,
the Masurian Canal

and its neighbouring base have
since been reclaimed by nature.

Their once formidable concrete
shells softened under

a veil of moss and leaves.

These hollow skeletal remains,

once bustling with
the frantic activity of warfare,

now stand as nothing more than
a haunting monument in

a landscape transformed by
the dark tides of history.

We have to wonder what the true
intent was for this canal.

Why was its construction kept secret
for so long?

And, more importantly,

how would the course
of history have changed had

the canal actually been completed
and that access to

the Baltic Sea had been opened up?

Subtitles by Red Bee Media