[Narrator] HIDDEN DEEP IN THE FORESTS OF GERMANY...

This is an impressive example of Nazi engineering.

...CONCEALED INSIDE VAST MOUNTAINS...

It's almost exactly like a Bond villain's lair.

...LIE THE REMAINS OF ONE OF THE MOST INTRIGUING ENGINEERING PROJECTS OF WORLD WAR II.

This is a do-or-die operation.

VAST UNDERGROUND FACTORIES BUILT FOR THE WORLD'S FIRST OPERATIONAL JET FIGHTER.

What they wanted to do was build the entire aircraft here.

THIS IS THE INCREDIBLE STORY OF THE ME262.

It's so sleek.

It's a thing of wonder.

Imagine what it must've been like to see this flying in 1944.

The Me 262 was the most advanced fighter aircraft of its time.

AND TO BUILD IT, THE NAZIS WILL CREATE A REVOLUTIONARY SUBTERRANEAN LAIR.

[Announcer] 'Nazi Mega Weapons THE BIGGEST CONSTRUCTION PROJECTS OF WORLD WAR II, ORDERED BY HITLER TO SECURE WORLD DOMINATION.

NOW THEY SURVIVE AS DARK REMINDERS OF THE FUHRER'S FANATICAL MILITARY AMBITION.

THESE ARE THE SECRETS OF THE NAZI MEGA WEAPONS.

GERMANY, 1945.

A FORCE OF ALLIED BOMBERS HEAD FOR HOME AFTER UNLEASHING THEIR DEADLY PAYLOAD, WHEN A MYSTERIOUS SHAPE SUDDENLY APPEARS IN THE SKIES.

[US Pilot] 'Fighters, 10 o'clock.

Coming in!

'Coming in on a half roll.

Pull her up, Chief!'

IT IS ADOLF HITLER'S NEW WONDER WEAPON, THE MESSERSCHMITT ME262, A REVOLUTIONARY PLANE WITHOUT PROPELLERS, CAPABLE OF FLYING UP TO 120 MILES PER HOUR FASTER THAN ANYTHING THE ALLIES HAVE.

AT THE CONTROLS IS ADOLF GALLAND.

'Bombers directly ahead.'

GALLAND HAS PILOTED OVER 700 COMBAT MISSIONS AND THIS IS THE FASTEST AIRCRAFT HE'S EVER FLOWN.

HE KNOWS THE JET'S INCREDIBLE SPEEDS GIVE GERMAN PILOTS THE EDGE IN AIR-TO-AIR COMBAT.

GALLAND RIPS THE BOMBERS APART.

BUT IT'S NOT JUST THE JET THAT'S AN AWESOME PIECE OF NAZI ENGINEERING.

JUST AS EXTRAORDINARY IS THE TOP SECRET FACTORY WHERE THE ME262 WILL BE BUILT AND MADE READY FOR WAR.

AN UNDERGROUND LAIR KNOWN AS THE REIMAHG.

Reimahg was an incredibly ambitious project, it was an enormous undertaking and very good example of Nazi engineering.

JET HISTORIAN, DR MIKE PAVELEC, IS ONE OF THE FEW PEOPLE TO HAVE BEEN ALLOWED INSIDE.

IT'S A COLOSSAL COMPLEX THAT WOULDN'T LOOK OUT OF PLACE IN A MODERN-DAY SPY FILM.

It's almost exactly like a Bond villain's lair, the combination of underground tunnels, concrete bunkers and a mountain-top air strip would've been ideal.

THE STORY OF THE REIMAHG FACTORY AND THE HIGH-TECH FIGHTER IT BUILT BEGINS IN THE 1930S, WHEN THE RACE IS ON TO PRODUCE THE WORLD'S FIRST JET AIRCRAFT.

WORLD WAR II HISTORIAN AND WRITER JAMES HOLLAND HAS STUDIED THE EARLY YEARS OF JET DEVELOPMENT.

In 1939, you've got at least 7 or 8 different jet engines being developed by various German aircraft manufacturers.

Pioneering work to a greater degree than any other country in the world.

MILITARY LEADERS WANT THE FASTEST PLANE IN THE SKY.

DESIGNERS REALIZE THAT PISTON-DRIVEN PROPELLERS ARE SELF-LIMITING, THEY LOSE THEIR EFFECTIVENESS AT HIGHER SPEEDS AND ALTITUDES.

Piston engines were reaching the end of their evolutionary stage, you couldn't improve them much more.

SO GERMAN AVIATION ENGINEERS LIKE WILLY MESSERSCHMITT EXPERIMENT WITH OTHER WAYS OF PROPELLING AN AIRCRAFT THROUGH THE SKY.

[Pavelec] What they came up with was turbojet engines.

This is the apex of Second World War jet technology.

It's an axial flow design which means the air flows straight through the entire engine to be exhausted out the back.

What you have here in this section is an eight-stage axial flow compressor.

The air would be drawn in from the front, compressed across this series of vanes, and forced into the combustion chambers here, where the gas is added to fuel, burned and expanded, which creates the thrust that powers the aircraft through the air.

ON AUGUST 27TH 1939, THE GERMANS LAUNCH THE WORLD'S FIRST JET AIRCRAFT.

THE BREAKTHROUGH MEANS THEIR AIR FORCE COULD SOON HAVE A MASSIVE ADVANTAGE OVER THEIR ENEMIES.

BUT RIGHT NOW, THE PLANE IS ONLY A PROTOTYPE, UNPROVEN IN BATTLE.

JUST FIVE DAYS LATER, HITLER INVADES POLAND.

WORLD WAR II HAS BEGUN.

AND LUFTWAFFE CHIEF HERMANN GOERING RELIES ON HIS PROPELLER PLANES TO WIN THE AIR WAR.

The leadership thought that the prop-driven aircrafts would be enough to run the victory and that there was no need for something spectacular, unusual and new like the Messerschmitt ME262.

WITHIN MONTHS, GOERING'S LUFTWAFFE CRUSHES THE ALLIES IN THE SKY AND ON THE GROUND.

BY SUMMER 1941, THE NAZIS OCCUPY MOST OF WESTERN EUROPE.

Confidence amongst the Luftwaffe is enormous, it's sky high.

The world has never seen the degree of conquest that the Germans manage, it seems they're completely unstoppable.

THE LUFTWAFFE'S SUCCESS DOES HAVE ONE UNINTENDED CASUALTY.

THEIR CONVENTIONAL PROPELLER PLANES PERFORM SO WELL, THAT THE NAZIS SCALE BACK THEIR JET PROGRAM.

DEVELOPMENT CONTINUES SLOWLY.

BUT BY 1943, THE TIDE TURNS.

THE GERMAN OFFENSIVE IN RUSSIA FAILS.

THE NAZIS ARE NOW ON THE DEFENSIVE.

AMERICAN AND BRITISH BOMBERS WREAK HAVOC ON THEIR INDUSTRIAL HEARTLAND.

THE GERMANS NEED A NEW WEAPON TO SEIZE BACK THE INITIATIVE.

Hitler is obsessed with wonder-weapons, and there are huge hopes for anything that involves dynamic and exciting new technology.

HOPES TURN TO GERMANY'S REVOLUTIONARY JETS.

BY 1943, ONE AIRCRAFT EMERGES AS A FRONTRUNNER IN THE NAZIS' JET PROGRAM: THE MESSERSCHMITT ME262.

IT OUTPERFORMS ANYTHING ELSE FLYING AT THE TIME AS JET FIGHTER PILOT GERHARD KRAEHENBUEHL KNOWS BETTER THAN MOST.

The Messerschmitt 262 was a quantum leap, having jet engines which give you a tremendous speed and a tremendous power which outranks all the propeller airplanes.

THE PLANE'S ENGINES POWER IT TO SPEEDS OF OVER 500MPH.

THE ME262 IS LIKE NOTHING EVER SEEN BEFORE.

The Nazis believed that this aircraft was potentially a war winner or at least this might be an answer to keeping American bombers out of the skies.

DETERMINED TO WIN HITLER'S FAVOR, LUFTWAFFE CHIEF HERMAN GOERING CHAMPIONS THE NEW ME262 PROTOTYPE.

BUT IT'S STILL AT TEST FLIGHT STAGE.

ADOLF GALLAND, COMMANDER OF THE LUFTWAFFE'S FIGHTER SQUADRONS, IS ONE OF THE FIRST PILOTS TO BE GIVEN THE CHANCE TO FLY IT.

AN ACE WITH OVER 90 KILLS TO HIS NAME, GALLAND'S APPROVAL COULD HELP GET THE NEW JET INTO FULL PRODUCTION.

He is one of the most respected combat pilots in the Luftwaffe, if not the most respected.

He's a pin-up, he's got bucket-loads of charisma, Goering loves him, the Nazis love him.

ON MAY 22ND 1943, GALLAND ARRIVES AT THE TEST CENTER.

HE KNOWS TAKING TO THE SKIES IN THIS EXPERIMENTAL PLANE IS A RISK.

A TEST PILOT HAS RECENTLY BEEN KILLED AND THERE HAVE BEEN PROBLEMS WITH THE NEW ENGINE.

This crate will probably shake me to death or break down at 3,000 meters, eh?

GALLAND IS STEPPING INTO THE UNKNOWN.

HE'LL BE FLYING 110MPH FASTER THAN HE'S EVER FLOWN BEFORE.

AS GALLAND LATER RECOUNTS, THE JET QUICKLY BLOWS AWAY ALL HIS DOUBTS.

'I could see that this aircraft was not just our last hope 'in the air war.

'I could see the future of aviation for the next century 'right in front of me.'

GALLAND THINKS THE ME262'S SPEED COULD ALLOW HIM TO STOP THE ALLIED ONSLAUGHT OF GERMANY.

Now if you're still a young guy like Galland is in 1943, '44, and there's some super new technology which enables you to fly aircraft even faster than anyone ever before, you're gonna grab that with two hands and say: 'Yes, give me a bit of that!'

WITH GALLAND BACKING THE PROGRAM, THE GERMAN AIR MINISTRY PUT IN AN ORDER FOR 100 PRODUCTION ME262S JUST A FEW DAYS LATER.

WILLY MESSERSCHMITT, THE AIRCRAFT'S DESIGNER, NOW NEEDS TO TURN THE EXPERIMENTAL JET INTO A PRODUCTION LINE PLANE AT HIS HIGH-TECH FACTORIES.

BUT THE PLAN SOON SUFFERS A SETBACK.

IN FEBRUARY 1944, THE ALLIES LAUNCH A HUGE BOMBING CAMPAIGN KNOWN AS 'OPERATION BIG WEEK'.

This is the attempt by the Allies to destroy the Luftwaffe once and for all, and frankly they do a pretty good job of it.

THE BOMBERS RAIN DOWN HIGH EXPLOSIVES ON AIR FORCE FACILITIES ALL OVER GERMANY.

That raid put back production schedules by about 6 months.

HIGH-TECH AIRCRAFT FACTORIES ARE PRIME TARGETS AND THE NEW ME262 PRODUCTION LINES ARE DESTROYED.

THEY NEED A SOLUTION IF THEY ARE TO BUILD HITLER'S NEW JET AND REGAIN CONTROL OF THEIR SKIES.

[Holland] The problem for Germany is they're now a nation in a hurry.

They've got to develop places where the Allied bombers cannot reach.

THE NAZIS DECIDE TO HIDE ME262 PRODUCTION ALL OVER GERMANY.

WINGS ENGINES AND FUSELAGES ARE BUILT IN FORESTS, CAVES AND TENTS.

BUT SCATTERING PRODUCTION MEANS DIFFERENT PARTS OF THE PLANE HAVE TO TRAVEL HUNDREDS OF MILES BEFORE ASSEMBLY CAN TAKE PLACE.

THEY NEED A SINGLE CENTRALIZED LOCATION WHERE A FAST ASSEMBLY LINE CAN BE RECREATED IN COMPLETE SAFETY.

IN KAHLA, 140 MILES FROM BERLIN, AN OLD PORCELAIN MINE THAT'S ALREADY BEEN EARMARKED FOR AIRCRAFT PRODUCTION COULD BECOME THE PERFECT HIDEAWAY.

BUT TRANSFORMING THE INSIDE OF A MOUNTAIN INTO A HIGH-TECH JET FACTORY IS SOMETHING THAT'S NEVER BEEN ATTEMPTED BEFORE.

HEADING UP THE PROJECT IS ONE OF THE MOST RUTHLESS MEN IN THE THIRD REICH: OBERGRUPPENFUEHRER FRITZ SAUCKEL.

Sauckel was put in charge to get it running and get the airplanes in the air.

FRITZ SAUCKEL IS AN EARLY NAZI PARTY MEMBER AND FANATICALLY LOYAL TO ADOLF HITLER.

HE IS NOW HEAD OF FORCED LABOR FOR THE REICH.

SAUCKEL WILL DO WHATEVER IT TAKES TO TRANSFORM THE OLD MINE COMPLEX INTO A FIGHTER-MAKING FACILITY.

He was a very driven personally, he was also pushed very, very hard from above.

HERMANN GOERING, HEAD OF THE GERMAN AIR FORCE, IS ANXIOUS FOR THE REIMAHG FACTORY TO BE BUILT QUICKLY.

It's still incredible to think of the enormous hold that Hermann Goering has over the Nazi war machine, and the Reimahg is just another example of this.

SAUCKEL PROMISES A BOMBPROOF FACTORY THAT CAN PRODUCE 1000 AIRCRAFT A MONTH.

We can start production of the site immediately and at the highest intensity.

I am confident the project will be a success.

BUT SAUCKEL FACES A MASSIVE CHALLENGE: BUILDING A HIGH-TECH PRODUCTION LINE UNDER A MOUNTAIN.

And they have to do all this in the last year of the war where everything is in short supply and in which the whole Third Reich's war effort is unbelievably stretched.

SAUCKEL HAS TO DELIVER BEFORE HITLER'S GERMANY IS BOMBED INTO OBLIVION.

This is a do-or-die, boom-or-bust operation.

IN 1944, CONSTRUCTION BEGINS ON THE NAZIS' UNDERGROUND FIGHTER LAIR.

FROM THE OFFSET, FRITZ SAUCKEL HAS A PROBLEM.

A MASSIVE ARMY OF WORKERS IS NEEDED TO BUILD THIS SUBTERRANEAN FACTORY.

BUT FOR THE HEAD OF FORCED LABOR IN HITLER'S REICH, THE SOLUTION IS OBVIOUS.

[German Officer] Out, quickly!

MARCEL VAN DEN STEEN IS A 23-YEAR-OLD LIVING IN BELGIUM WHEN THE GESTAPO ABDUCT HIM FROM HIS PARENTS.

OK, OK, I'm coming!

MARCEL KEEPS A SECRET DIARY DURING THE WAR YEARS.

IT PROVIDES RARE INSIGHT INTO THE BRUTAL CONDITIONS FACED AT SAUCKEL'S REIMAHG FACILITY.

[German Officer] Out, quickly!

[Marcel] 'We were forced into a truck and then a train 'and we were taken to Kahla.'

[Marcel] Where are we?

[Officer] No talking!

Walk!

MARCEL IS ONE OF 12,000 FORCED LABORERS TRANSPORTED ACROSS EUROPE AND FORCED TO WORK AT REIMAHG.

IT IS THE BEGINNING OF A LIVING NIGHTMARE.

It quickly became obvious that Fritz Sauckel had utter contempt for human life and he used a number of slave laborers brought in from camps specifically for this program.

THE WORKERS MUST FIGHT TO SURVIVE.

THEY HAVE TO COMPLETE THE TUNNELS BEFORE SAUCKEL CAN BEGIN BUILDING PLANES.

A staggering amount of energy, logistical effort, resources, human and financial, and materials are being put into creating this.

INCREDIBLY, THE RUINS OF FRITZ SAUCKEL'S MASSIVE PROJECT STILL REMAIN, HIDDEN IN A CLEARING IN A REMOTE PART OF GERMANY.

THE BROKEN RUBBLE, SILENT WITNESS TO THE NAZIS' OBSESSION WITH THE ME262.

MIKE PAVELEC WANTS TO EXPLORE UNDERGROUND AT THE REIMAHG FACILITY, BUT ACCESS IS LIMITED AND EXTREMELY DANGEROUS.

There is another way... LOCAL HISTORIAN, MARCUS GLEICHMANN, IS ON HAND TO LEAD THE WAY.

[Pavelec] Oh, you gotta be kidding me!

TO TRAVEL BACK TO SAUCKEL'S SECRET WARTIME TUNNELS, THEY HAVE TO HEAD DEEP UNDER THE WALPERSBERG MOUNTAIN.

[Gleichmann] It's not too easy to find the right path.

[Pavelec] I would imagine.

It's good we got you here.

MIKE AND MARKUS ACCESS THE TUNNEL SYSTEM THROUGH THE ONE REMAINING ENTRANCE.

ALL OTHER WAYS IN AND OUT HAVE BEEN SEALED OFF.

TREKKING HALF A MILE UNDERGROUND, THEY ARRIVE AT PRODUCTION TUNNELS THAT WERE BEING DUG IN 1944.

Sauckel's plan for this place was to build the entire aircraft here.

Jets, the engines, the components, the fuselage, everything.

THE NAZIS HAVE TO BUILD AN UNDERGROUND FACTORY WHERE THEY CAN ASSEMBLE A 42-FOOT WIDE PLANE.

PLANNERS ENVISION 75 SEPARATE TUNNELS MEASURING 9 MILES.

THOUSANDS WILL BE EMPLOYED ON THIS IMMENSE TASK OF ENLARGING THE EXISTING PORCELAIN MINE AND BUILDING THE NEW FACILITY.

INCLUDING BELGIAN FORCED LABORER, MARCEL VAN DEN STEEN.

WORKERS ARE SELECTED FOR HEAVY OR LIGHT DUTIES DEPENDING ON THEIR STRENGTH.

[Marcel] This is not good.

[Officer] You worthless piece of dirt!

You're a light worker!

16-HOUR SHIFTS WITH NO BREAKS ARE COMMONPLACE.

[Pavelec] This place would've been enormously difficult to build.

Imagine having to remove all of the material from inside these tunnels, putting it outside.

But just digging through this sandstone and then reinforcing it and building a production center under a mountain.

CONDITIONS IN THE TUNNELS ARE TERRIBLE.

WORKERS ARE FORCED TO DIG WITH LITTLE EXPERTISE AND BASIC TOOLS.

UNSTABLE BANDS OF SLATE IN THE CEILING ABOVE MEANS THAT TUNNELING IS A LIFE-OR-DEATH GAMBLE.

ESPECIALLY IN AREAS WHERE SAUCKEL PLANS TO BUILD EVEN WIDER TUNNELS AND BIGGER HALLS.

[Pavelec] This is very impressive.

[Gleichmann] It is one of the largest tunnels in this system.

THE AIRCRAFT ASSEMBLY HALLS ARE PLANNED TO BE AT THE CENTER OF THE MOUNTAIN.

COMPONENTS BUILT IN SMALLER TUNNELS WILL BE FED INTO THIS WORKING AREA WHERE THE ME262 CAN BE PUT TOGETHER.

[Gleichmann] The plan was to build it 450 meters in length and at a height of 5.5 to 6 meters, and a width of 15 meters, so that the whole airplane would fit in here.

BUT A CAVE THIS BIG MIGHT COMPLETELY COLLAPSE DURING CONSTRUCTION, SO THE NAZI ENGINEERS COME UP WITH A LOW-TECH FIX.

RATHER THAN EXCAVATING ONE BIG TUNNEL, WORKERS DIG FOUR SMALLER TUNNELS SO THE WEIGHT OF THE CAVE ABOVE REMAINS SUPPORTED.

WITHIN THESE FOUR TUNNELS, THEY GRADUALLY SECURE THE CEILING OVERHEAD AND BUILD UP THE FOUNDATIONS WITH CONCRETE.

THEN THEY HOLLOW OUT THE CAVE UNTIL JUST TWO COLUMNS OF ROCK REMAIN.

ONCE THESE ARE REMOVED, A SPACE BIG ENOUGH FOR A FIGHTER JET IS CREATED.

[Pavelec] It was big enough in here for a full-size ME262?

[Gleichmann] Yeah.

[Pavelec] Very impressive technology.

All this was done by hand?

[Gleichmann] Yes, all this is done by forced laborers from all over Europe.

THE NAZIS HAVE LONG-TERM PLANS TO PRODUCE 750 JETS A MONTH AT THE REIMAHG FACILITY, BUT BUILDING THE FULLY FUNCTIONAL FACTORY IS TAKING MUCH LONGER THAN THEY HOPED.

AND THIS ISN'T THE ONLY CHALLENGE THE ME262 PROJECT FACES.

WILLY MESSERSCHMITT HAS BUILT THE WORLD'S FASTEST JET FIGHTER, BUT IT IS SO REVOLUTIONARY, THE NAZIS ARGUE OVER HOW BEST TO USE IT.

EVER SINCE ITS CONCEPTION, ADOLF HITLER HAS STRONG OPINIONS ON HOW TO EXPLOIT THE JET'S DEADLY CAPABILITIES.

Messerschmitt, is the aircraft able to carry bombs?

Yes, my Fuhrer, it can carry for sure a 250-kg bomb.

This is the Blitz bomber I have been requesting for years!

What Hitler wants to do is have an aircraft that can knock an invasion force back into the sea.

So he thinks a fighter bomber which can combine the role of being a fighter and drop bombs, is the answer to that.

BUT ADOLF GALLAND THINKS THAT WEIGHING DOWN THE AERODYNAMIC ME262 WITH A BOMB WILL SLOW IT DOWN.

HITLER IS DESTROYING THE JET'S MAIN ASSET AS A FIGHTER, ITS SPEED.

[Pavelec] Galland thought that Hitler's request to make the aircraft a bomber was absurd.

Galland knew that the ME262 was the point interceptor fighter that he was looking for to clear the Allied bombers from the skies.

[Hitler] If the Atlantic invasion comes, it can easily fly through enemy defenses, attack ground targets and escape at speed.

You, Messerschmitt, have to make all the necessary preparations to make this feasible.

[Galland] 'This was really the beginning of the misuse 'of the ME262.

'I felt my heart sink at that moment.'

HITLER IS MORE CONCERNED ABOUT ATTACKING THE ENEMY THAN PROVIDING HIS FIGHTER PILOTS WITH THE JET THEY NEED TO DEFEND GERMANY FROM ALLIED BOMBERS.

IF GALLAND IS GOING TO CHANGE HOW THE ME262 WILL BE USED, HE HAS TO TAKE ON THE TOUGHEST OPPONENT IN THE THIRD REICH: THE FUHRER HIMSELF.

[Holland] Galland knows how to play the game.

He knows how to manipulate and talk to the right people and get what he wants.

GALLAND ENLISTS THE HELP OF THE ARMAMENTS MINISTER ALBERT SPEER, A CLOSE CONFIDANT OF THE FUHRER.

[Galland] Given the tactical situation, we believe the best we can do is use this aircraft as a protective fighter force at our critical industries.

[Hitler] No!

Never!

I will order a halt to all fighter aircraft production.

If you persist in this, I will have the fighter arm disbanded!

- But... - I've heard quite enough!

[Holland] This is how Hitler paints the war.

It's how he's always seen the war.

He's a man of extremes.

There's no middle ground, it's always one or the other in his mind.

BEFORE LONG, HOW THE GERMANS USE THE ME262 IS GOING TO BE LESS CRITICAL THAN HOW QUICKLY THEY CAN GET THEM INTO THE AIR.

THE ALLIES ARE PLANNING TO LAUNCH THE LARGEST INVASION ARMADA EVER SEEN AGAINST HITLER'S FORTRESS EUROPE.

AT THE REIMAHG FACILITY, FRITZ SAUCKEL'S UNDERGROUND PLANE FACTORY IS A LONG WAY FROM COMPLETION.

THE DIE-HARD NAZI PUSHES HIS WORKERS TO THE LIMIT.

All men must be fed, sheltered and treated in such a way as to exploit them to the highest possible extent and the lowest conceivable degree of expenditure.

HERMANN GOERING PROMISES HITLER THAT WHEN THE ALLIED INVASION COMES, THE GERMAN AIR FORCE WILL SMASH THEM ON THE BEACHES.

GOERING NEEDS AS MANY PLANES AS HE CAN GET AND PUTS THE PRESSURE ON SAUCKEL TO GET THINGS MOVING.

BUT HE MIGHT BE TOO LATE.

JUNE 6TH, 1944.

D-DAY, THE ALLIED INVASION OF FRANCE.

THOUSANDS OF TROOPS AND TANKS POUR ASHORE, TAKING ON HITLER'S ATLANTIC WALL.

NONE OF THE NEW NAZI WONDER JETS ARE AVAILABLE TO THROW THE ALLIES BACK INTO THE SEA.

WORSE, THE LUFTWAFFE FAILS TO PROVIDE THE AIR SUPPORT THE GERMAN TROOPS NEED.

GOERING'S PROMISE IS FALSE.

THE ALLIES SECURE THEIR FOOTHOLD AND ADVANCE INTO MAINLAND EUROPE.

IT SIGNALS THE BEGINNING OF THE END FOR THE THIRD REICH.

IN DESPERATION, WORK ON THE REIMAHG ME262 FACTORY STEPS UP A GEAR.

BELGIAN LABORER MARCEL VAN DEN STEEN IS ONE OF 12,000 LABORERS FORCED TO WORK 16-HOUR SHIFTS OVERSEEN BY BRUTAL SS GUARDS.

[SS Officer] It's gone up.

One slice of bread is 4 cigarettes.

[Sauckel] You swine!

Back to work!

SAUCKEL PUSHES MARCEL AND HIS FELLOW WORKERS EVEN HARDER.

STARVED OF FOOD AND WITH THE ONSET OF WINTER, MARCEL SEES THE DEATH TOLL RISE ALONG WITH THE LEVELS OF BRUTALITY.

[Marcel] The workers get thrashed here like dogs, and so many have died in the last six months.

I saw someone dying on the floor.

I wasn't even allowed to help him.

A German guard kept shouting, 'Leave him, keep walking, pigs!'

1,500 PRISONERS WILL DIE AT THE REIMAHG FACILITY.

BY WINTER 1944, THE FACTORY UNDER THE MOUNTAIN IS STILL NOT READY.

THE NAZIS ARE FORCED TO CONSTRUCT BUILDINGS OUTSIDE OF THE TUNNELS WHERE THE PRODUCTION OF PLANE PARTS CAN GO AHEAD, INCLUDING MASSIVE BOMBPROOF BUNKERS.

[Pavelec] Bunker 1 was the final stage assembly of the Messerschmitt 262, where they took the fuselage that was built elsewhere, and the wings that were built here, and put it all together.

BUNKER 1 IS 328 FEET LONG AND 49 FEET WIDE, TOPPED BY A ROOF THAT CAN WITHSTAND ALMOST ANYTHING THAT ENEMY BOMBERS CAN THROW AT IT.

Even though it doesn't look much today, you get a sense of how thick the walls were.

The roof was probably 5 meters - 25, 30 feet thick, of reinforced concrete that could withstand an Allied bombing attack.

THIS BUNKER IS ONE OF A LINE OF MASSIVE STRUCTURES CONSTRUCTED ON THE SOUTHERN SLOPE OF THE MOUNTAIN.

THE REMAINS OF THESE FOUR BUNKERS AND ITS SUPPORT NETWORK OF WORKSHOPS CAN STILL BE FOUND TODAY.

WITH SAUCKEL'S UNDERGROUND FACILITIES NOT READY, THESE BUILDINGS ARE FORCED INTO ACTION AS THE MAIN ASSEMBLY LINE FOR THE NEW JET.

The above-ground facilities like this one were built because they were very quickly constructed and the pressure to get the Messerschmitt 262 flying was enormous by this point in the war.

BY JANUARY 1945, THE NOOSE IS BEING TIGHTENED ON GERMANY.

THE ALLIES HAVE PUSHED BACK HITLER'S LAST GREAT COUNTER-OFFENSIVE DURING THE BATTLE OF THE BULGE.

AND THE RELENTLESS BOMBING INCREASES THE NEED FOR ME262S.

[Holland] Most Germans know that the war is not going to be won.

The tide has turned too sharply, but Hitler is still clinging onto this thousand-year Reich concept.

ACROSS THE REICH, NEARLY ALL OF HITLER'S AIRCRAFT FACTORIES ARE FORCED INTO BUILDING THE NEW WONDER JET.

HERE IN NORTHERN AUSTRIA ARE THE REMAINS OF A VAST FEEDER FACTORY CALLED BERGKRISTALL.

BERGKRISTALL SUPPLIED FUSELAGES FOR THE JETS BEING ASSEMBLED AT THE REIMAHG FACILITY.

THE NAZIS HERE WOULD ALSO BE GUILTY OF SOME HORRIFIC WAR CRIMES.

This huge underground installation was built in only 13 months by inmates of concentration camp Gusen Two.

They excavated partly by hand with shovels, with hydraulic drills, not with huge machinery.

STARVATION, BEATINGS AND DISEASE AT GUSEN TWO MEAN THAT IT WOULD EARN THE NICKNAME 'THE HELL OF HELLS'.

A healthy young man had an average survival period of only three months.

THE CAMP'S TEMPORARY BARRACKS LACK EVEN THE MOST BASIC INFRASTRUCTURE, WITH AN AVERAGE OF 500 INMATES CRAMMED INTO A SINGLE BUILDING.

IN LESS THAN A YEAR, 9,000 WILL DIE.

SURVIVOR, DUSAN STEFANCIC, REMEMBERS THE STENCH OF DEATH WHEN HE FIRST ARRIVED.

The first impression was horrible, because before the barrack there was a pile of naked dead bodies.

EVERY DAY, DUSAN WAS TRANSPORTED TO BERGKRISTALL TO BUILD ME262 PARTS.

Life was not worth anything, because you had to work.

If you were unfit for work, you were then annihilated.

You were brought to a place actually where in one way or another you were killed.

SLOW WORKERS WOULD BE HUNG IN FRONT OF THE OTHER PRISONERS.

[Stefancic] Once somebody was sent to Gusen Two, it was then like he had been condemned to death.

218 MILES NORTH AT THE REIMAHG FACILITY, MARCEL VAN DEN STEEN AND HIS FELLOW WORKERS ARE ALSO PUSHED TO THEIR BREAKING POINT.

[Marcel] My future here is looking bleak.

I'm suffering here like it's hell, but I don't want to die here for Hitler.

BUT FRITZ SAUCKEL'S CRUEL REGIME BEGINS TO PAY OFF FOR THE NAZIS.

HIS WORKERS ARE FINALLY READY TO ASSEMBLE COMPLETE ME262S FOR THE FIRST TIME.

The resources and effort required to do that are just absolutely enormous, and yet they do it.

It never ceases to amaze me the lengths to which the Nazis go to continue their war effort.

SAUCKEL'S ATTENTIONS TURNS TO THE NEXT CHALLENGE: HOW TO GET HIS NEW PLANES INTO THE SKIES ABOVE NAZI GERMANY?

GERMANY'S RAILWAYS HAVE BEEN BOMBED INTO OBLIVION AND REIMAHG IS IN THE MIDDLE OF NOWHERE The problem that Fritz Sauckel runs into is: How do you get the aircraft where they need to be, their combat-operational squadrons?

There isn't a clear place anywhere in this valley to put an airfield.

So he comes up with either the craziest idea in the world or the most ingenious idea in the world, and that is to put an airstrip on the top of this mountain to move the aircraft out of this valley.

REIMAHG'S VERY OWN TAKE-OFF SITE WILL HAVE TO BE AT LEAST 3,280 FEET LONG TO LAUNCH THE NEW JET.

MARCEL VAN DEN STEEN WAS ONE OF OVER 1,000 WORKERS FORCED TO WORK UNDER STRICT GUARD.

[Pavelec] Building the runway was an impressive undertaking.

All of these trees had to be cleared, the top soil had to be cleared, in addition to the concrete that had to be brought to the top of the mountain to build this runway.

THE LABORERS EVENTUALLY LEVEL OFF THE TOP OF THE MOUNTAIN AND FORM A CONCRETE RUNWAY.

SAUCKEL IS IN A RUSH TO LAUNCH THE WUNDERJET.

BUT THE PLANES ARE STILL AT THE FACILITY, 278 FEET BELOW.

MIKE IS ON THE HUNT IN THE FOREST ALONGSIDE REIMAHG'S RUINS TO FIND OUT EXACTLY HOW SAUCKEL HAULS A FIGHTER PLANE TO THE TOP OF A MOUNTAIN.

These are the concrete pilings that the wooden trestles would have laid across.

FIVE-FOOT WOODEN TRESTLES ARE KEPT IN PLACE BY CONCRETE FOUNDATIONS THAT STILL REMAIN TODAY.

What this is, is an image taken at the end of the war, 1945.

The picture is of the elevator that took the ME262 from this level up to the top of the mountain.

THE ASSEMBLED ME262 IS HAULED ON A WHEELED PLATFORM UP A RAIL ON THE SOUTHERN SLOPE OF THE MOUNTAIN TO THE RUNWAY ABOVE.

OVER 1,000 WORKERS ARE EMPLOYED IN EXECUTING SAUCKEL'S AMBITIOUS VISION.

The human and engineering effort to get an aircraft up 660 feet at a 25-degree incline is enormous.

What this tells us is the Nazis were incredibly desperate, trying to get aircraft from bombproof production facilities up this mountain to an airfield at the top, in order to get them into the war as fast as possible.

BY JANUARY 1945, WORKERS FROM FACTORIES ALL ACROSS GERMANY HAVE GIVEN HITLER JUST 500 OPERATIONAL ME262S.

IT'S NOT ENOUGH.

BUT THE FUHRER'S HAS GIVEN UP ON HIS FIXATION OF USING THE JET AS AN ATTACKING BLITZ BOMBER.

Hitler finally relents, allows the ME262 to be developed specifically as a fighter, and after that the argument is over.

THE FUHRER GIVES ORDERS ALLOWING ADOLF GALLAND TO FORM HIS OWN JET FIGHTER UNIT.

HE ASSEMBLES GERMANY'S TOP GUNS INTO AN ELITE SQUADRON... Heil Hitler!

...HIS AIM TO FINALLY PROVE THE ME262 IS THE PERFECT DEFENSIVE FIGHTER.

We are to form the ultimate fighter squadron.

We will be flying 262s as fully operational fighters.

We have full rein to deploy them as we see fit.

Gentlemen, welcome to the future of air war.

ME262S ARE RUSHED INTO BATTLE ACROSS GERMANY, AND THE DRIVE TO GET MORE OF THESE JETS INTO THE AIR IS IMMENSE.

NOWHERE IS THIS PRESSURE MORE OBVIOUS THAN AT THE REIMAHG FACILITY.

MIKE PAVELEC TREKS FURTHER UP THE WALPERSBERG MOUNTAIN TO FIND OUT MORE ABOUT JUST HOW THE AIRCRAFT WAS HAULED UP THE STEEP INCLINE.

What we have here is the top of the aircraft elevator system.

This was probably the wheelhouse for the entire elevator.

What that means is there were machinery components in here that ran the cables to bring the aircraft platform to this level.

THE RUNWAY IS NO LONGER VISIBLE, LOST TO THE FOREST.

IN 1945, IT WOULD BE FROM THIS LEVEL THAT SAUCKEL'S NEW JETS WOULD HAVE TO TAKE OFF.

BUT 3,280-FOOT RUNWAY WILL BE DANGEROUSLY SHORT FOR A NEW JET FIGHTER.

[Pavelec] They could have never landed if they had a problem, because it was too short a runway to land.

They had to go where they were going, there was no coming back.

FEBRUARY 21ST 1945.

THE BIG LAUNCH.

LIFT-OFF FROM THE SHORT RUNWAY WILL BE TOUCH AND GO.

MARCEL AND SOME OF HIS FELLOW WORKERS ARE ALLOWED TO WITNESS THE RISKY FIRST FLIGHT.

[Marcel] 'I hope he crashes.'

MARCEL MAY GET HIS WISH.

AGAINST ALL ODDS, REIMAHG'S FIRST ME262 SOARS INTO THE SKIES.

SAUCKEL HAS DELIVERED HIS FIRST JET TO THE FUEHRER.

From an engineering point of view, you've got to take your hat off to them, it's astonishing what they managed to achieve.

MARCH, 1945.

THE NAZIS DRIVE TO GET THE NEW JETS INTO THE SKY SHOWS NO SIGNS OF DIMINISHING.

THE ALLIES ARE ON THE BORDERS OF GERMANY.

THE SOVIETS SET THEIR SIGHTS ON HITLER AND BERLIN.

THE GERMAN CAPITAL ALREADY LIES IN RUINS.

THERE ARE NOT ENOUGH JET FIGHTERS TO DEFEND THE CITY FROM BOMBERS.

BUT HITLER WILL NEVER ALLOW SURRENDER.

IN ONE FINAL ACT OF DEFIANCE, HIS ENGINEERS FAST-TRACK A ME262 FACTORY THAT TAKES THE INSANITY OF THE THIRD REICH TO A WHOLE NEW LEVEL.

IN MUHLDORF, FORTY MILES FROM MUNICH IN SOUTHERN GERMANY, LIE THE REMAINS OF ONE OF THE MOST REMARKABLE NAZI STRUCTURES EVER BUILT.

A DESPERATE LAST-DITCH IDEA TO BOLSTER THE ME262 PRODUCTION LINE AND GIVE THE NAZIS MORE OF THE NEW JETS THEY NEED.

This is the last remaining arch of a huge bunker structure that was planned and partly built by the Nazis during the last months of World War II.

THESE REMAINS OF NAZI ARCHITECTURE WERE ONCE A VAST BARREL-SHAPED BUNKER BUILT USING ARCHES MADE OF POURED CONCRETE.

The purpose of this bunker was to build parts for the Messerschmitt 262 fighter airplane.

IT IS PLANNED TO BE 1,312 FEET LONG WITH NINE STORIES BELOW, PRODUCING 900 JETS A MONTH.

This is a very impressive example of Nazi engineering.

INCREDIBLY, THIS STRUCTURE CAN WITHSTAND A DIRECT HIT FROM A 6-TON BOMB.

[Pavelec] This is fantastic.

How would you have built this?

They had a mountain of gravel for the form.

Under here?

Under here where we're standing now.

And on top of this gravel mountain, they would build the concrete.

EACH SEPARATE ARCH SECTION IS BUILT ON TOP OF A HUGE MOUND OF GRAVEL WHICH IS REMOVED ONCE THE REINFORCED CONCRETE IS SET.

BUT HOW DID THE WORKERS MOVE THIS GRAVEL ONCE THE ARCH HAD BEEN CONSTRUCTED?

THE DARK SECRET LIES BENEATH THE EARTH IN THIS SECLUDED FOREST.

LOCAL HISTORIAN MICHAEL GAERTNER SEARCHES FOR CLUES FROM GERMANY'S NAZI PAST.

You can see the dimensions of the gravel removal tunnel which was big enough to host a railway.

AN UNDERGROUND RAILWAY RUNS BENEATH THE ENTIRE LENGTH OF MUHLDORF'S VAST FIGHTER JET BUNKER.

CARRIAGES ARE MOVED INTO POSITION BELOW, ALLOWING THE FAST REMOVAL OF THE GRAVEL ABOVE.

A good part of the gravel came down itself by gravity, but there were prisoners working by hand removing the gravel from the carriages.

10,000 WORKERS ARE EMPLOYED ON THE PROJECT, 8,500 OF THEM FORCED LABORERS AND INMATES OF A NEARBY CONCENTRATION CAMP NETWORK.

OF THESE, MORE THAN 3,000 WILL DIE.

During the construction, the prisoners had to run with cement bags of 50 kilos on their backs, and it would happen that they would slip out and just fall down into the liquid concrete and drown there.

DESPITE THE HORRIFIC LOSS OF LIFE, ONLY 7 OF THE 12 INTENDED ARCHES ARE BUILT.

THE GERMANS ARE MONTHS OFF COMPLETING THE FACTORY, AND NO FIGHTERS WILL EVER BE MADE HERE.

JUST ONE OF THE MASSIVE ARCHES NOW REMAINS, A MOVING MONUMENT TO THE HUMAN COST OF THE ME262.

The whole thing is insanity.

It's another sign of the way in which the final year of the Third Reich is just going more and more into the realms of fantasy world.

IT IS A FANTASY THAT WILL SOON BE BROUGHT TO AN ABRUPT END.

BUT FIRST, NAZI FIGHTER ACE, ADOLF GALLAND, STILL HAS A POINT TO PROVE.

HIS ELITE UNIT OF FIGHTER ACES TAKES TO THE SKIES TO ATTACK ALLIED BOMBERS.

This was a golden opportunity for Adolf Galland to finally prove his contention that the Messerschmitt ME262 was the best fighter in the skies.

This is very much the last huzzah, the last cavalry charge, so to speak, of the Luftwaffe.

GALLAND'S NEW JET FIGHTERS ARE 120MPH QUICKER THAN THE FASTEST ALLIED PLANES.

AND GALLAND CAN USE THEM AS HE WANTS, GUNNING DOWN SLOW MOVING BOMBERS AT HIGH SPEED.

One of the major tactics was: don't touch the throttles, climbing to high altitudes, holding the air, waiting for your targets, and then dashing through the targets, with the speed that guns can't follow and especially also the prop fighters can't follow.

MARCH 18TH, 1945.

37 ME262S TAKE ON OVER 1,300 ALLIED AIRCRAFT.

THE HEAVILY OUTNUMBERED GERMANS SHOOT DOWN 13 OF THE ATTACKERS FOR THE LOSS OF JUST THREE JETS, A RATIO OF OVER 4:1.

THE ME262 PROVES HOW DEADLY IT CAN BE, BUT IT IS TOO LITTLE, TOO LATE.

[Holland] The Luftwaffe, by the end of the war, didn't have enough pilots to fly these things.

They didn't have enough fuel to fly them.

They didn't have enough maintenance units to maintain them.

[Pavelec] The Germans had a wonderful weapon.

It was simply outnumbered by American and British material superiority.

APRIL 12TH, 1945.

THE AMERICANS ADVANCE TOWARDS THE REIMAHG FACILITY.

THE TROOPS ARE STUNNED BY WHAT THEY DISCOVER.

A HIDDEN SUBTERRANEAN FACTORY BUILT TO CREATE AN AIRCRAFT THAT LOOKS LIKE SOMETHING OUT OF SCIENCE FICTION AND THE CAMPS OF THE LABORERS THAT WERE FORCED TO CONSTRUCT IT.

Let me see your hands!

AFTER EIGHT MONTHS' IMPRISONMENT, MARCEL VAN DEN STEEN IS A FREE MAN.

[Marcel] 'I don't believe this, my heart is beating.

'I just want to kill those men that made us suffer.'

BUT FRITZ SAUCKEL IS NOWHERE TO BE SEEN.

HE IS NOW A NAZI ON THE RUN.

HIS PLAN TO BUILD HUNDREDS OF JETS AT THE REIMAHG FACILITY HAS FAILED.

[Pavelec] By the end of the war, when this installation was taken over by the Americans, only 24 or 26 ME262s had left this installation, gone up the elevator and taken off from this very short runway.

Obviously not enough aircraft to change the course of the war.

ADOLF GALLAND WOULD RIDE HIS LUCK TO THE BITTER END AND PAY THE PRICE.

[Galland] 'My canopy was shattered, 'and my right knee was struck by a bullet.

'I was losing power and in great pain.'

GALLAND SOMEHOW MANAGES TO SURVIVE THE CRASH.

HE IS LATER CAPTURED AND TAKEN TO ENGLAND WHERE HE WOULD BE INTERROGATED ABOUT THE ME262.

ON MAY 9TH 1945, FRITZ SAUCKEL, THE MAN RESPONSIBLE FOR REIMAHG, WAS EVENTUALLY CAPTURED AT HITLER'S MOUNTAIN RETREAT.

HE IS LATER TRIED AT NUREMBURG FOR HIS CRIMES AND EXECUTED.

ALONGSIDE HIM IN THE DOCK IS HERMANN GOERING, WHO CONTINUED TO BELIEVE THE ME262 COULD HAVE WON THE AIR WAR IF MORE OF THEM HAD BEEN BUILT EARLIER.

BUT BY THE TIME IT CAME INTO COMBAT IN 1944, THE SHEER NUMBERS OF ALLIED AIRCRAFT IN THE SKIES HAD OVERWHELMED THE NEW JET.

IT MAY NOT HAVE TURNED THE TIDE OF THE WAR, BUT THE ME262 PAVED THE WAY FOR THE JET AGE.

MESSERSCHMITT'S DESIGN FEATURES CAN STILL BE SEEN IN EVERY TURBO JET POWERED COMBAT AIRCRAFT THAT TAKES TO THE SKIES.

EVEN THE CUTTING-EDGE EUROFIGHTER.

[Holland] There are different strands to the legacy of the ME262.

First of all, it's the first operational jet fighter aircraft and that alone is significant.

The second thing really that is its legacy is that experimental work that was going on on aerodynamics and aircraft, air-frame design, which the rest of the world benefited from hugely post war.

THIS WAS AN AIRCRAFT THAT WOULD NEVER BE FORGOTTEN.

Anyone who has even just the remotest love of aviation cannot help but be seduced by the ME262, but you can't escape its origins and how it was built in horrific conditions in underground factories, by a monstrous regime that was just responsible for some incredible level of misery and death and mayhem.

[Announcer] 'Nazi Mega To learn more about this program or any of the other episodes in this series, visit us online at... Nazi Mega Weapons is available on DVD.

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