Original subtitles

Perched atop Europe's towering hills,

along the banks of its grand rivers,

and within the beating heart of its most lucrative trade centres,

stand the bastions of its past -

the majestic castles of former kingdoms.

For centuries, these structures have stood

as silent sentinels of history,

weathering wars

and enduring the elements even as progress engulfed

the world around them.

But when the ominous shadow of

the Third Reich falls across the continent,

these once mighty fortresses are transformed into symbols of a new

and foreboding era.

As the Nazis unleashed their brutal conquest of Europe,

the structures, left behind by regimes of

the past, take on a new significance.

They're seized and repurposed

to serve the dark ambitions of the Reich.

The Nazis' relentless advance leave no stone unturned.

One by one,

the castles of central Europe succumb to the regime's iron grip,

each restored to a twisted version of their former glory.

This brash conquest of architecture brings Hitler closer

to his vision of dominance,

a Nazi Reich built on

the foundations of Europe's storied past.

The Nazis are going to claim

and repurpose these castles for a variety of reasons.

These castles could be used as military bases,

as military headquarters for smaller operations,

smaller regional operations.

These once majestic structures slowly transformed into

the underbelly of the Nazi war machine.

Yet beyond the stagnant moats

and the tall fortress walls,

the activities that transpire within remain shrouded in secrecy,

largely hidden from

the world until the collapse of the regime.

Why were these castles specifically picked by the Reich?

What dark dealings were concealed behind the walls?

Characterised by their formidable walls,

rugged stonework, and imposing silhouettes,

castles are the architectural marvels that once shaped

the landscape of medieval Europe.

Often equipped with defensive towers,

moats and a labyrinth of chambers,

these structures are built to keep enemies out,

and the secrets of their dynasties within.

Far more than defensive strongholds,

here stand the political headquarters where the fate of

a kingdom is decided by both pen and sword,

The epicentre of near absolute power.

These structures have been around for a long, long time, and as

different cultures,

different people influence these structures,

they change, they morph.

You can sort of see the postmark of a particular influence.

In the 20th century,

despite their prominent place in the European landscape,

many of these castles were

no longer used as centres of power.

Some castles were still the centre of power for rulers,

others were occupied by noble families,

but many more had become tourist

attractions or had been converted into hospitals,

and some had even been abandoned and fallen into disrepair.

Yet, for some,

the dwindling significance

of Europe's prestigious properties makes them all the more alluring.

And soon many would be consolidated under

the control of Europe's most evil regime.

Germany, 1933.

As Hitler's political ambitions take hold,

so too does his vision for reshaping the architectural landscape

of Europe.

Foreseeing an empire of unprecedented might,

he enlists the aid of Albert Speer,

one of the nation's finest architects.

Albert Speer is a committed Nazi.

He is very loyal to Hitler,

and Hitler really sees in him, kind of, this visionary who will be able

to create a new German Reich.

And together they begin drafting the blueprint

for what will become infamously known as the Thousand-Year Reich.

The Thousand-Year Reich was Hitler's attempt to try

and rebuild a modern Roman Empire,

but in his own twisted, racial vision.

And so this was an empire that was

going to be inhabited by racially pure Aryans.

He uses these structures as

political tools capable

of instilling fear and awe to crowds.

Architecture is really important in this pursuit

to establish a Thousand-Year Reich.

In his role as dictator,

Hitler uses architecture as an instrument of power.

In the lands beneath the German flag,

however, preservation is paramount.

In addition to erecting new architectural showpieces,

Hitler claims thousands

of existing structures as rebranded monuments of the SS,

the most impressive of which are

the age-old palaces of central Europe.

As Nazi influence spreads across Germany and beyond,

the region's most magnificent castles are folded into

the arms of the Reich.

But what use could Hitler make of these centuries-old buildings,

some of which had been long vacant and now stood dilapidated?

Though no longer serving the need of a kingdom,

the grandeur of some palaces had been

meticulously maintained since

their inception in the Middle Ages.

One such structure is

the 9th-century Prague castle that looms over

the capital of modern-day Czech Republic.

This castle has essentially been built up to be

a city within a city.

It encompasses everything, from palaces to offices

to churches and even gardens.

It's been the seat of power for rulers,

kings and presidents for over 1,000 years.

For centuries, Prague Castle stands

as an emblem of Bohemian pride

and sovereignty.

From this historic seat of power,

the region's most influential rulers have governed.

And in 1939,

one man is intent on claiming it for himself.

As the Nazi Party gains control of Germany,

Hitler is all consumed by a lust for power.

He soon sets his eyes on the military

and economic resources of the neighbouring Czechoslovakia.

In March 1939,

when Hitler presents his ultimatum

to Czech President Emil Hacha,

Hacha finds himself in a horrific situation.

He's being told by Hitler,

"If you don't surrender your country to me,

"I will unleash fire and fury and destroy it with my army."

Ultimately, he decides to spare

the many lives that would certainly be lost in battle

and surrenders his nation to Hitler.

Some sources say this was such a tense decision,

that Hacha suffers a heart attack as a result.

Hitler's forced invasion of Czechoslovakia is

the first step in his planned occupation of Europe.

At the break of dawn, Nazi troops flood the border,

their Fuhrer close behind,

and as they push into the Czechoslovakian capital,

Hitler brashly seizes the seat of authority,

the presidential office and dwelling of Prague Castle.

It's a conscious, symbolic move by Hitler

to arrive in Prague Castle

and have himself photographed there in 1939.

And this picture served great propaganda purposes.

They even used it on a postage stamp.

Why? It's showing Hitler as

the latest ruler in this long line of Bohemian rulers.

With Hitler's arrival, Czechoslovakia is no more.

In its place rises the Protectorate Of Bohemia And Moravia,

now a mere extension of Nazi Germany.

Hitler's cruel conquest of Europe has begun.

On the Fuhrer's first night enclosed

in the ancient castle walls,

Hitler is said to proudly survey his new possession,

one that harbours the finest treasure in all the land.

Locked away in the castle's St Vitus Cathedral

lies a chamber of glittering gold.

In the sacred chapel corner, behind a door guarded by

the spirits of saints interred on site, is

an impenetrable iron vault.

Here, secured by seven individual locks,

rests the Bohemian crown jewels -

priceless ornaments donned in

royal coronations since the 14th century.

The Bohemian Crown Jewels represent Czech peoplehood

and sovereignty,

and they connect the contemporary Czechoslovakian state

to a long history of independence and sovereignty.

The Crown Jewels include

a number of precious items amassed throughout

the castle's history.

This includes the St Wenceslas crown,

which is a masterpiece of pure gold encasing more than

100 precious stones.

The seven keys to the crown jewels

are traditionally dispersed among

the nation's most revered political

and religious figures, including, most notably,

the president.

Yet, as Hitler's forces stormed the castle,

Emil Hacha is forced to relinquish his key to the invaders.

The castle, and the precious heirlooms it guards,

fall to Hitler's trusted official

and perhaps one of the darkest minds of the Reich.

Reinhard Heydrich is one of the rising stars of the Nazi Party

when he is appointed as the Reich Protector of Bohemia and Moravia,

but at this time he has turned himself into one of

the most powerful members of the Third Reich.

Heinrich Himmler, the head of the SS, is de facto right-hand man.

Hitler himself calls Heydrich

"the man with the iron heart."

But he's more widely regarded as

the Butcher of Prague.

Under his rule,

thousands of dissenting citizens face execution,

while tens of thousands more perish

in the squalid conditions of his ghetto

or the brutal concentration camps that it services.

All the while, in the comforts of the castle,

Heydrich is said to familiarise himself with

the riches locked behind the chapel walls.

We don't know for sure,

but rumours have always held that

Heydrich was particularly interested in,

and even obsessed with, the Bohemian crown jewels,

and people even say that he actually put

the St Wenceslaus crown on his head.

Local lore warns that any usurper who dares to don

the St Wenceslaus crown is doomed to meet a gruesome end

within a year's time.

Though it remains uncertain whether Heydrich truly places

the crown upon his head,

he lasts a mere eight months in Prague before his vicious day

of reckoning arrives.

The resistance movement that grows up in Occupied Czechoslovakia

really has their sights set on killing him,

and one group eventually is successful.

A grenade was thrown at the vehicle

and detonated just outside of

the car, mortally wounding Heydrich.

Heydrich doesn't die immediately,

but he does succumb to his wounds a couple of days later.

Heydrich's death, however,

means little to a regime intent on

maintaining their claim by any means necessary.

Within just 24 hours,

another SS commander takes his place,

holding the Reich's ominous control from the palace over Prague.

In the northern reaches of the East Prussian province,

another ancient fort is transformed into

a Nazi institution.

Among the first of the castles to fall to

the Reich is Marienburg, today known as Malbork.

A sprawling brick compound in modern-day Poland,

this colossal structure is

the largest castle in the world by land area,

occupying a plot of 52 acres,

or 210,437 square metres,

along the edge of the river Nogat.

This castle is unique.

When I look at it,

you immediately recognise the colour of it.

It doesn't look like that sort of fairy tale vision of what

a castle might be.

Marienburg Castle is

a massive red-brick structure

that's situated in what was once known as East Prussia.

It's believed that this structure is

built up from more than 30 million individual bricks.

That castle was a former castle of the Teutonic Knights.

The Teutonic Knights were a kind of

a crusading order of warrior monks,

just like the Crusaders that went to Jerusalem,

except they went east

into Russia,

into what will become Russia,

into what will become the Ukraine and Poland.

The castle is an ordensburg,

a fortified monastery designed to cement their hold of

the Baltic lands by acting as both a defensive fort

and a launch point

for further invasions in the region.

That history allowed Hitler to link his Nazi movement

with this medieval Germanic society,

and he'd like to do that a lot.

Whether it's Vikings

or the Teutonic Knights or old Germanic religion,

he liked to claim that what he was doing was

a continuation and a revitalization

of what he saw as true Germanic heritage.

Whether that's religious, military, or cultural.

In 1933,

the Nazi flag is hoisted above the high castle.

Once a relic of the Middle Ages,

Marienburg is transformed into

an ideological nerve centre of the Reich.

A new iteration of ordensburg,

no longer guarding a monastic society,

but rather the education of Nazi elite.

So Hitler's aim is not only to establish the Nazi regime,

but ensure that that regime is

upheld by future generations of Germans.

So the role of these schools was to produce

the next generation of politicians,

civil servants,

and generals who were going to succeed in

the continued administration of the Third Reich.

The ordensburg curriculum is

completed in four phases

at different castles across the Reich.

Hitler envisions Marienburg as the final,

crucial enrolment before

the indoctrination of its pupils is complete.

The sprawling campus is planned to house 1,000 students

and 500 hand-picked staff members at a time.

Its spacious courtyard will be filled with

the crack of live fire military drills,

and its lecture halls will echo with

the impassioned political rhetoric -

the perfect facility to forge a new generation of German might.

Marienburg was the ideal place to set up this project.

It was incredibly spacious,

and most of its facilities had been well-maintained over the years.

With infrastructure complete and the programme approved,

Marienburg is readied for its first students.

But in 1939,

the siren of war abruptly halts enrolment as young men are diverted

to duties along the front lines.

But the castle grounds don't fall silent.

Instead, the building's grand refectory comes alive

with nationalist zeal.

The Grand Refectory is the largest hall

in the Marienburg Castle complex.

It has huge vaulted roofs and 14 tall windows.

Prior to occupation,

this room was a very ceremonial room,

but a celebratory one. It was where feasts would be had,

kings' feasts with the various royalty,

and it would be a place of celebration and lightness.

As plans for an ordensburg are set aside,

the castle gates remained open to

an entire population of Hitler youth.

Here, beneath the magnificent vaulted ceilings of

the grand refectory,

the children of the Reich will conclude

a political pilgrimage by swearing an eternal oath

to their glorified Fuhrer.

Why bring children so far from the heart of Germany

to swear this oath in some of

the most far flung reaches of Hitler's empire?

They established the Hitler Youth as well as

the League of German Girls.

So boys and girls are going to be enlisted.

And, after 1936,

this becomes compulsory that all German boys

and girls must join these youth groups.

Hitler Youth are shuttled to Marienburg in droves,

where they swear allegiance to Hitler beneath

the blood banner,

a Nazi flag said to be soaked by

the blood of Nazi martyrs.

As it billows above the borderlands,

pennants of the Teutonic knighthood

are soon ceremoniously revived across the castle grounds.

By 1936,

Hitler mandated that German children were

to join these youth organisations.

Now, obviously, what he meant by that was that children

that are considered to be Aryan would join.

those that are not would obviously be forbidden.

Propagandists declare a day of return

to ancient symbols of the order.

A spectacle designed

to captivate their most impressionable adolescent minds.

Hitler famously said, "Whoever has the youth, has the future."

And what he really means by that is that if you can

control the minds of the youth,

you can ensure that they think the way that you want them

to do when they become adults in the future.

As a young man,

Adolf Hitler himself was captivated by

the romantic allure of European castles.

Long before his sinister ambitions took hold,

his sketchbook was filled with

the intricate details of towering stone facades

and imposing turrets that adorned the German countryside.

For Hitler, these drawings were more than mere artistic exercise,

but windows into a world of potential,

a dream waiting to be seized.

Among these architectural musings was Neuschwanstein Castle,

a majestic structure nestled in the foothills of the Bavarian Alps.

This castle, it's iconic.

It is in this mountainous region

with forests, deep forests,

and...and it's positioned on an elevated point,

and it looks like it's out of a dream.

This actually inspired Walt Disney

for the Magic Kingdom.

And you can see that parallel.

It's quite clear there.

Unlike its medieval counterparts

scattered across central Europe,

this mist-shrouded fortress is dated to just the 19th century,

an era that rarely saw new castles being erected.

Born from the whimsical desires of an extravagant monarch,

it stands as a monument to aesthetics rather than authority.

Neuschwanstein Castle is commissioned by

King Ludwig II of Bavaria.

And Ludwig II is also referred to as Mad King Ludwig,

and he was a great patron of the arts.

He was very interested in art and music.

He loved the music of Richard Wagner,

but he was also a quiet man who wanted to be able

to find a place where he could kind of retire

and be away from, kind of,

the hustle and bustle of his daily activities.

Another fan of Wagner is Adolf Hitler.

Murals of Wagner's Parsifal opera illuminate

the singer's hall,

while paintings of European folktales enliven

the parlours and study.

As beautiful inside as it is out,

this private paradise cements Ludwig II's legacy as

the fairy tale king. However,

he himself only enjoys its splendour for a brief time.

In 1886, before the castle can be completed,

he drowns under mysterious circumstances.

And half a century later,

Hitler's watercolour fantasy is brought to life as

the Nazis claim Neuschwanstein as their own.

In a region engulfed by war,

why would the Nazis invest resources into this secluded bastion

tucked away in the Alps?

It's not until May of 1945,

as the Reich begins to crumble

beneath the Allied onslaught,

that the true purpose of this castle is unveiled.

Tracing a trail of records from a museum in France,

a special Allied task unit,

famously known as the Monuments Men,

is led up the winding path to Neuschwanstein.

On the Eve of the Nazi surrender in Bavaria,

they enter the unguarded palace,

unaware of the staggering discovery that awaits within its walls.

The Monuments Men were a group of Allied soldiers with

a background in art history or curation or museum work,

and their goal was

to protect priceless cultural treasures

from the depravity of war.

As the Allies pushed into Germany

and Nazis begin to surrender,

the Monuments Men were tasked with finding

and recovering plundered art - works of art that were stolen

and pillaged by the Reich.

They knew that this happened,

but they really weren't aware of the extent.

When the Monuments Men enter Neuschwanstein

and discover this cache of over 20,000 artefacts

and items that had been looted by the Nazis,

they notice that there is in the corner of these works of art,

the inscription ."ERR.

Hidden behind the ornate doors of

the palace chambers lies a dark wartime secret.

Neuschwanstein Castle, once a peaceful sanctuary,

has been transformed into a storehouse of plunder.

ERR stands for the Reichsleiter Rosenberg Taskforce.

The ERR was established by Hitler

and the directive was

to go into museums, libraries,

and families' personal homes and take any items

and artefacts of any value.

Room after room is crammed with crates,

shelves and chests overflowing with priceless relics.

Furniture and sculptures are piled high to the ceilings.

The Nazis kept meticulous records,

and that habit, or that practice, benefits

the Monuments Men in their mission.

It helps them establish

the provenance of these paintings that were looted and plundered.

So I think Hitler also did have this ambition to develop

the Fuhrer Museum, and obviously

to make that museum world-class

and one that would have the...

the best pieces of art from around

Europe was, was probably something that Hitler was aspiring to.

Throughout the course of the War,

it's estimated that the ERR is responsible for

the theft of over two million artworks

and three million culturally important books.

To store their poached goods,

the Nazi organisation sets up

a regional headquarters at Neuschwanstein,

and beneath the castle's fairy tale facade,

a full-scale looting operation unfurls.

Neuschwanstein is this incredible secluded castle,

really in the middle of nowhere,

in the foothills of the Bavarian Alps.

However, clearing the castle of

its ill-gotten loot would prove

to be a gruelling task.

Navigating this castle is difficult,

let alone it being packed with crates

and boxes of precious pieces of art and sculptures

and various artefacts.

One by one, the Monuments Men must

carefully carry 600 crates

of invaluable treasures down four floors of steep,

winding staircases,

a process that takes over six weeks to complete.

Clearing that out,

moving that, is a project on its own as well.

While Neuschwanstein will long be remembered as

a gilded cage for stolen valuables,

a different kind of clandestine operation unfolds

some 500km to the north, in the German state of Saxony.

Here, concealed behind chapel walls,

lavatories and phantom partitions,

a maze of chiselled tunnel snakes beneath

the grounds of Colditz Castle,

not dug by the Nazis but by those they have captured.

Colditz Castle is a Renaissance-era fortress,

but sits atop a hill overlooking the Mulde River.

In a castle of this scale, there are,

there's several passageways.

There are nooks and crannies. There are big cellars.

They're thick walls.

Sound doesn't necessarily translate through these thick walls.

Over its history,

it's been used for a number of different purposes,

including a zoo and a psychiatric hospital,

but always with

the intention of keeping its residents contained within.

The seemingly impenetrable Colditz Castle rests atop

a steep, craggy hill and is encircled by a two-metre thick wall.

Each door is guarded

and each window fortified with strong iron bars.

And the reason for this is Colditz is where

the Germans put their most problematic POWs.

And what I mean by problematic,

the ones that were the most effective at escaping.

However, as resistance begins to simmer,

only a select class of prisoners are chosen

to be contained here,

high-ranking officials who are prone to escape.

So Colditz Castle is a little bit of a paradox.

So on the one side,

you've got this amazing fortress

that you can securely place all these problematic POWs

that are regularly escaping.

But by putting them all together,

you're allowing all these escape artists to collaborate

with each other. So in many aspects,

you're creating a whole new problem.

Escape attempts were numerous throughout World War II,

and some Allied officers were especially talented in this pursuit.

For those that were caught in the act,

many of them would be funnelled to Colditz Castle,

now known as Oflag IV-C.

To locate your prison facility away from

the borders of any states, any,

any other states means that once you escape that prison,

if you manage to escape the prison,

traversing all that distance without getting caught is survivability

really. That's the... That's the issue.

Oflag IV-C quickly gained infamy across Europe for being

the only German prison with more guards than inmates.

For prisoners to achieve a clean break,

they must navigate a series of daunting obstacles,

descending unnoticed to the main floor,

crossing terraces under armed watch,

and clearing a courtyard with just two exit points.

If they can make it here,

then they must surmount a barrier of barbed wire

and scale a massive defensive wall,

beyond which lies a 75-metre drop into

the murky river below.

In the eyes of the Nazis,

Colditz is escape-proof.

But nothing will stop their inmates from trying.

Now, despite being one of

the most heavily fortified prisons,

Castle Colditz actually has

the highest success rate for escapes.

Because of the intricacies of

the circulation throughout this building,

there's blind spots.

The guards would not be able

to have eyes on all of these different locations.

And the group

of prisoners here were experts

in exploiting those blind spots

and creating distractions

and creating opportunities to squirrel away in

a small area that's unsupervised and start digging a tunnel.

In April 1941,

French officer Alain le Ray becomes

the first Oflag IV-C captive to flee the castle cells,

covertly darting into an outbuilding during

a guarded excursion to the prison park.

Many others that attempt to follow utilise

a maze of tunnels burrowed through the castle grounds,

including Le Metro,

a 140-metre-long shaft manoeuvring through a clock tower,

two floors of cellars,

and ending just steps

from the edge of the Colditz Cliff.

Colditz contains a number of hidden passageways,

large cellars and thick walls,

which create a number of nooks

and crannies that prisoners can exploit

to assist in their attempts to escape.

The most daring escape pursuit of all,

however, is set to be airborne,

using a blind spot on the tall chapel roof

and a makeshift glider plane.

The engineers draft the specification for

the escape glider using

a textbook they actually found in the prison library.

Building a glider?

That's tough with limited materials,

you're scrounging up whatever you can get your hands on,

from bed slats to...to furniture

to pieces that you can pry off of that furniture,

to sheet metal that you might come across,

small pieces of material.

And then it also needs to be light enough to fly, essentially.

And these people aren't aircraft designers.

They're, they're winging it!

The departure date is set for spring of 1945,

when a pulley system will send

the 240lb plane soaring off a wooden runway from

the chapel roof. Fortunately, however,

this perilous scheme is interrupted when American troops stormed

the castle, liberating its detainees

and rendering an escape unnecessary.

Over 800km to the east, in annexed Poland,

other inmates are not so fortunate.

Here in the city of Lublin,

the Nazis lay claim to a 14th-century Gothic fortress,

where the sombre reach

of their power truly begins to emerge.

Lublin Castle is a large,

rectangular-shaped fortress

overlooking one of

the oldest cities in Poland.

In the 19th century,

the castle is under Russian occupation

and the Russians transform it into a prison,

and it houses primarily Jewish and Polish people,

and they are treated really, really poorly by the Nazis.

Erected on a hill that rises above a marshy plain,

Lublin Castle was once a near impregnable fort.

But as Russian, and later Polish, authorities took hold,

they would transform this stronghold into

a place of dread.

Built to hold a maximum of 700 inmates...

SS officials, with callous disregard for human dignity,

pushed the structure far beyond its limit.

The prison is overcrowded.

There is a distinct lack of food,

the conditions are terrible,

and many of the prisoners die of hunger as well as disease.

Lublin Castle is chosen not just as an ordinary prison,

but a holding centre for trials,

interrogations and, in many cases,

executions at the hands of his merciless Gestapo.

Upon arrival,

prisoners were often taken to

a building called Under The Clock,

named for the clock at its entrance.

And there they would be subjected

to brutal interrogation

and torture at the hands of the Gestapo.

Many people did not emerge alive.

Some were ordered to remain within

the horrid halls of Lublin,

others are condemned to immediate death.

And yet, still worse, many are sent on to Majdanek,

one of the largest concentration camps in the Reich.

Immediately after the Nazis take power,

they start opening concentration camps.

And a Nazi concentration camp is a brutal prison that

the Nazis used to put their enemies,

and they are to be used and exploited,

whether that is used to slave labour or to be killed.

Among the atrocities committed at Majdanek

and other camps will be the use of

an abhorrent technology,

the result of a dark experiment conducted in

the confines of another faraway fortress.

Situated in a rural Austrian village

along the River Danube,

Hartheim Castle is

a quintessential Renaissance-style structure built in

the 17th century.

Its symmetrical stone facade encloses

a serene courtyard framed by four storeys of classic arches.

Once run by a Catholic sisterhood,

the setting was a refuge for physically

and intellectually disabled citizens in the north country.

At the end of the 19th century,

Hartheim Castle has become a care home for the disabled

and includes about 200 patients.

Following the annexation of Austria to Germany,

management of the facility is handed over to the Reich.

Although the care home remains operational

for existing patients,

the Nazis abruptly restrict public access.

The Nazis took this space

and transformed it into a progression of death and murder.

Locals begin to wonder what's happening in Hartheim Home.

Families are no longer allowed to visit their loved ones,

and people start to wonder if

the patients are being taken care of.

Though barred from its inner workings,

soon locals can't escape

the nauseating fumes that permeate their fields and streets.

To quell public concern,

Hartheim's director, Christian Wirth,

concocts a calculated lie.

The smoke, he claims,

is merely the by-product of

an oil processing machine vital for German U-boats at war.

However, suspicion heightens yet again when relatives of

the institution's residents begin

receiving a flurry of death notices.

In 1939,

this 4,000 square metre building undergoes

a complete transformation to accommodate its new function.

The top floor is transformed into a storage area for

the belongings confiscated from the prisoners.

The middle two floors were turned into offices,

quarters and kitchens for use by the onsite staff.

But it's the ground floor that would be transformed into

a chilling new killing centre.

The four wings surrounding

the courtyard are reconfigured into

a harrowing assembly line to fulfil the agenda of

the Nazi's Aktion T4 project.

Hartheim is no longer a care facility,

but a centre for mass extermination.

Patients brought to Hartheim by bus are discreetly unloaded

in a covered garage

to shield their arrival from public view.

They are then ushered into

a series of adjoined holding rooms in the north wing,

where they are greeted by nurses before undergoing

a cursory medical examination.

The facility's renovation is designed to deceive.

The prisoners were led through

a series of rooms that culminated

in what was called the shower room.

And whenever you hear the word "shower"

in the context of Nazi Germany,

you should prepare for something horrible.

This seemingly standard procedure will not lead

to treatment, because under the Fuhrer's command,

Hartheim Castle has been transformed

into one of six designated euthanasia facilities in the Reich,

a station of the monstrous Aktion T4.

This was a room that they were locked inside,

and then poison gas was let in, and they were murdered.

Aktion T4 is a covert operation initiated by the Nazis

to kill people who were considered "unworthy" of life.

In a grim Nazi experiment,

over 100 individuals are trapped inside,

and 20 minutes later, not a single person emerges alive.

By 1941,

the volume of murders here is so high

a second chimney has to be installed on site.

They also disposed of a lot of

the ashes by pouring them

into an offshoot of the Danube River

that flowed near the castle.

Hartheim Castle is an effective venue for this

because it is secluded

and it also allows

for Hitler's terrible operations to be masked.

The Hartheim showers claim the lives of

an estimated 30,000 innocent people,

including children,

just a fraction of the total euthanised

across Hitler's Aktion T4 centres.

Amidst the killings, burners,

nurses and medical staff regularly gather

to celebrate their murderous milestones.

Hartheim Castle was used throughout the war

as a killing centre

for prisoners of concentration camps.

On December 11th, 1944, as Germany faces the loss of war,

the Nazis carry out their final act

of gassing at Hartheim Castle,

silencing the last concentration camp victims

to be suffocated by the Reich.

All remnants of their deplorable crimes

at the site are destroyed.

The chimney is dismantled and the ovens demolished,

hoping to obscure the full extent of their cruelty

from the eyes of both history and justice.

For the Nazi regime to destroy evidence

and to not leave behind any remnants

of the awful, heinous,

brutal acts that they were carrying out is essentially

a way for them to exonerate themselves

from the awful acts that they committed.

Among these enigmatic structures is Houska Castle,

a Gothic edifice in the modern-day Czech Republic.

Built in the 13th century,

it stands as one of the most well-preserved castles of its era,

complete with a grand chapel,

maintained chambers

and intricately painted murals.

In the wake of the Nazi invasion,

the Wehrmacht seized this ancient vestige,

but their reasons for doing so

remain in question to this day.

Houska Castle doesn't seem

to have any strategic value.

It's in the middle of nowhere.

It is filled with all these strange symbols

and references. So why did the Nazis claim it?

Additionally, the castle has no kitchen facilities

or running water supply,

making its use all the more puzzling.

Inside the castle chapel,

a series of 14th-century frescoes tell a curious tale.

Dedicated to the biblical Archangel Michael,

known for leading an army

against the forces of Lucifer,

the chapel paintings depict vicious battle scenes

and dead souls on the Day of Judgement.

The frescoes inside this chapel are quite unusual

because they combine Christian symbolisms

and stories with these pagan symbols and myths.

Some say the reason for

the SS capture lies beneath the soil,

a feature that has haunted the imaginations of locals

and visitors for centuries.

Here, under the thick stone floors,

a seemingly bottomless chasm yawns into the darkness,

a void that some believe leads

straight to the depths of Hell itself.

Legends about this pit

in Houska Castle date back to the 13th century.

Even before the castle was built,

this pit was said to be a gateway to Hell.

Local lore has long warned

of evil forces roaming these Bohemian forests,

tales of otherworldly creatures

and winged demons scouring

for souls have all found their origin in this deep abyss.

And the story goes that

the king of Bohemia in the mid-1200s, Ottokar II,

offered prisoners condemned to death

a pardon if they would agree to go down into this pit

and see what was actually going on down there.

And according to local legend that's been passed down over the centuries,

when these prisoners emerged from the pit, they'd age rapidly.

Shortly after this,

King Ottokar II actually has

a castle built around this pit

to protect the community from whatever was down below.

According to some,

this portal to hell may have held special interest

to Adolf Hitler's right-hand man, Heinrich Himmler,

one of the primary conductors of the Holocaust, who held

an obsessive interest in the occult.

Heinrich Himmler was one of

the most powerful men in Nazi Germany.

As head of the SS, he wielded enormous power,

but he was also exceptionally evil.

He is overseeing the most vile

and evil organisation in Nazi Germany.

Some theories suggest that Houska plays host

to Nazi occult ceremonies

and experiments that summon Satanic forces to win

the war and rule the world.

This theory gains credence in 2016,

when around 13,000 books on the topic of the occult

and witchcraft are unearthed from

a Nazi vault near Prague, all amassed by Himmler himself.

And the fact that Houska Castle has this strange,

dark, kind of foreboding history

and mythology that links the occult

with kind of these symbolisms of paganism

and Satanism is one reason why

we might think that perhaps this is why the Nazis wanted it,

that it was, in fact, the gateway to Hell.

The fall of the Reich in 1945

eventually sees Nazi-occupied castles reclaimed by

the regions that birthed them.

Though most reminders of Nazi rule

of these ancient sites have since been erased,

they will inevitably harbour

horrific memories for decades to come.

The Nazis were responsible for untold death,

suffering and devastation throughout

the territories that they ruled.

We're still discovering the extent of that today.

So you have to ask yourself,

what other evidence of evil acts is still hidden,

still buried underneath castles or behind

the walls of these historic structures?

Though Nazi Germany often restored these castles

to their engineered splendour,

they would forever taint

the legacy of those who constructed them.

These architectural marvels will now forever bear

the memory of Nazi Germany and the atrocities committed within.

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