Nova (1974) s39e11 Episode Script
3D Spies of WWII
NARRATOR: It's the early days of World War II.
Hitler's armies storm through Europe, crushing everything in their path.
Western Europe is on the brink of defeat.
The Allies turn to the iconic Spitfire to help change the course of the war.
Now, the fighter plane is not armed with weapons that kill, but with one that will keep them one step ahead of the Nazi war machine.
A surveillance camera.
British and American pilots fly dangerous missions to gather critical intelligence.
JOHN S.
BLYTH: My job was as a photo reconnaissance pilot.
It was a wonderful airplane to fly.
I loved it.
It had cameras, no guns.
NARRATOR: In a country house located 35 miles west of London, a team of brilliant minds analyzes the tens of millions of aerial photos taken during the war and recently declassified for the first time.
MIKE MOCKFORD: Nothing moved in Europe which we did not photograph, and it was utterly critical to the Allied success in the Second World War.
NARRATOR: The photo interpreters have a secret weapon to expose German secrets.
Using stereoscopes, they bring the Nazis' world to life in 3D.
DINO BRUGIONI: In 3D, the first thing, you can get height.
Also at the same time you can measure very effectively, too, the width.
NARRATOR: Using this technology, an obscure photograph reveals evidence of one of Hitler's most secretive and most lethal weapons programs.
MOCKFORD: In today's terminology, the V weapons were the first weapons of mass destruction.
NARRATOR: How did a handful of photo interpreters so far from the battlefields succeed in derailing Hitler's wonder weapons? BRUGIONI: Working night and day, they saved thousands and thousands of lives.
NARRATOR: "3D Spies of World War II," right now on NOVA.
Major funding for NOVA is provided by the following: Supporting NOVA and promoting public understanding of science.
And the Corporation for Public Broadcasting and by PBS viewers like you.
Additional funding from: Inspiring tomorrow's engineers and technologists.
NARRATOR: September 1939, Germany invades Poland and the Second World War is under way.
Adolf Hitler launches an all-out assault.
One European nation after another crumbles.
JOE MAIOLO: The German strategy was to win as quick a war as they possibly could.
NARRATOR: Britain is the last nation standing.
Just eight months after invading Poland, Hitler is poised for domination.
The battle for Europe unfolds in the skies over Britain.
Defeating German airpower falls to Britain's most advanced fighter plane, the Spitfire.
BLYTH: When I was in high school, the Battle of Britain was on, and the Spitfire was the only aircraft actually that could compete against the Germans.
NARRATOR: Nearly four months later, the Spitfire and her heroic pilots helped to win the Battle of Britain.
But the victory is short-lived.
The Germans begin a relentless nine-month bombing campaign against British cities.
The Blitz leaves more than 40,000 civilians dead.
To strike back at German cities, the Royal Air Force needs more accurate and up-to-date intelligence.
Aerial photographs are the key.
ROBERT EHLERS: Photographic reconnaissance was exceptionally important.
80% of British intelligence came from photo interpretation.
It allowed operational commanders to point their heavy bombers at the right targets.
NARRATOR: Once again, military leaders turn to the Spitfire.
Now, it will be armed not with guns, but with cameras.
The Spitfire is transformed from a killing machine into a spy plane, the Allies' eyes in the sky.
It is redesigned to fly faster, higher, and farther.
Retrofitting the Spitfires with the new cameras is not a simple task.
JIMMY TAYLOR: It had five cameras.
One was fitted under each wing here and two in the fuselage.
And these were vertical cameras.
The big ones were for the high level, of course, and the small ones were for the low level.
NARRATOR: The F52 camera, the most sophisticated of the day, is the weapon of choice.
With its large image format and lenses with longer focal lengths, it can take detailed photos like these from altitudes of up to 30,000 feet.
TAYLOR: The camera's here.
As you can see, it's a pretty big one, and that would have to be put through this hatch here and point down through one of these two portholes in the bottom of the fuselage.
NARRATOR: The missions take pilots deep into German territory.
There is a constant fear of being intercepted and shot down.
And at 30,000 feet, temperatures plummet to minus-50 degrees.
BLYTH: It was cold.
They bled off most of the warm air to heat the cameras to keep the film going.
Sometimes your knees you could hardly bend them or anything.
NARRATOR: Taking photos that are useful to intelligence analysts requires extraordinary skill.
When they found their target, they had to fly a level course because if they weren't flying straight and level, it distorted the pictures.
You would have to get right over the target, practically, and roll over and see the target and then bring the airplane around and level out and fly straight and level while the cameras were turning.
NARRATOR: Reconnaissance pilots take tens of millions of photographs during the war.
Many, only recently declassified, are kept here, at an archive in Edinburgh, Scotland.
Researcher Allan Williams is working with retired RAF Wing Commander Mike Mockford and Major Chris Halsall, both photo interpreters after the war, to track down the photos that helped defeat the Nazis.
MOCKFORD: Nothing moved in Europe which we did not photograph, and it was critical to the Allied success in the Second World War.
CHRIS HALSALL: Without air reconnaissance, it is difficult to imagine how we could have possibly achieved the results we did.
NARRATOR: The key to their success lies in a meticulous three-phase interpretation process that starts at the airfield.
TAYLOR: They would look at the photographs and if something needed immediate action, within 24 hours, say, where the army had to shell or the air force had to bomb some target NARRATOR: The photos are then rushed to a Royal Air Force base at Medmenham, a country estate 35 miles west of London.
TAYLOR: They'd send all the more important photographs to Medmenham because they had interpreters there, and there were 2,000 of these by the war's end, all specialized in different sections, and they would then identify whether there was something that could be bombed or attacked in the next week or so, which was phase two, or whether it was a long-term thing about the German war effort, and they contributed to the to phase three.
NARRATOR: Deciding which photos are priorities is critical.
The interpreters must decipher every last detail from the images.
But their analysis is only as good as the material they have to work with.
This is an aerial photo of the elite German battleship the Tirpitz.
MOCKFORD: You can see all the guns, you can see the crew on the deck, and nobody has moved.
I suspect the crew on the deck are probably stunned by the noise of the aircraft.
HALSALL: That photograph, what is acknowledged to be probably one of the closest-ever shots of a major German capital ship.
NARRATOR: But for analysts at Medmenham, photos taken at an oblique angle have limited value.
Instead, pilots must shoot the photos while looking straight down and from a much higher altitude.
MOCKFORD: The vertical photograph is your intelligence analysts' ideal: no hidden ground, easy to scale because it's like a map.
You really can see very clearly exactly what you've got down there.
NARRATOR: The vertical photos allow the interpreters to employ one of their greatest intelligence weapons: a stereoscope, which enables them to see in three dimensions.
Now, they expose details previously invisible, allowing them to accurately select their targets and assess damage after bombing raids.
For it to work, the pilots must take the photos in an overlapping sequence.
TAYLOR: We had to make sure that when they were viewed by the photo interpreters, each of these pictures overlapped the other by 60%, because everything on the photograph would then stand up in three dimensions.
NARRATOR: These two photos show a Norwegian fjord.
When overlapped under the stereoscope, the brain fuses them into one, creating the perception of depth, so the fjord appears in three dimensions.
The benefits are immediate.
This photo reveals what appears to be a German ship in the middle of the fjord.
MOCKFORD: The ship itself, with all its preparation for camouflage, is very unusual.
In fact, I think there's something exceedingly odd about this particular ship and the image, and you'd see this very clearly in three dimensions.
NARRATOR: 3D allows analysts to see something they wouldn't have seen otherwise: the true position of the ship concealed along the shoreline.
HALSALL: Going offshore, there is this decoy and boom combined where they've lashed together tires in the water, joined them all up together, and made them look like a ship floating in the water.
NARRATOR: The work at RAF Medmenham plays an increasingly vital role in the war effort, and the job of the photo interpreters, or PIs, requires the top minds.
EHLERS: It's stunning when you think about it, because the British had their pick of the very best people who could see things.
Photo interpreters had to have 20/20 vision.
STONE: They recruited a lot of academics, and particularly academics who were accustomed to being precise.
ELIZABETH HICK: A lot of them were recruited from Oxford and Cambridge: mathematicians, geologists, archaeologists.
NARRATOR: Interpreting photographs is not just an academic skill.
Finding hidden details requires a creative mind.
Once the U.
S.
enters the war in 1941, Medmenham looks to Hollywood for talent.
Walt Disney legend and imagineer Xavier Atencio, who later helps create the Pirates of the Caribbean, is part of a large American contingent at Medmenham.
XAVIER ATENCIO: I was assigned to airfields.
That's how I became an expert on airfields.
We had quite a few artists in our unit because we had an eye for detail.
MARGARET HURLEY: A lot of them were very handpicked.
Yes, I wasn't.
A lot of them were.
NARRATOR: By 1942, with a brilliant team at Medmenham in place, the RAF plans a bold new strategy.
Aerial intelligence is key in identifying targets.
Their top priority is to figure out a way to strike a crippling blow to Hitler's war machine.
They plan to raid dams in the Ruhr Valley, the source of the Nazis' hydroelectric power supply and the heart of their weapons industry.
Located deep in the heartland of Germany, these are not easy targets.
Success depends on detailed information about the dams.
MOCKFORD: Medmenham played a huge role.
They prepared most all the pre-targeting information.
They designed and built the models on which much of the planning was done for the dams' raid.
Before the dams' raid took place, Medmenham were critical in telling the bomber commands-- the squadron and the bomber command-- when the dams had sufficient water in to make the bomb effective, because they had to wait until the water level rose to a certain point.
NARRATOR: The Spitfire images alone will not be enough for such a precision bombing mission.
A state-of-the-art machine called the Wild is used to make precise measurements from aerial photos.
EHLERS: It was a photogrammetric machine that could measure distances, so they knew not only how big an object was, but what the distance was between objects.
They were able, very precisely, to know where to put their crosshairs.
NARRATOR: Within hours of the Dambusters raid, spy planes assess the damage.
The dams are breached and the Ruhr valley is flooded, disrupting vital German industries.
MOCKFORD: The air ministry phoned Medmenham and spoke to the man who was doing the damage assessment and said to him in a very excited voice, apparently, "What's it like, what's it like, how big is the breach?" you know.
And they were really hanging on every word and he gave him the answer over the phone: they breached two dams.
There was terrible devastation and awful loss of life, but, um we were fighting for our life.
NARRATOR: 3D aerial photography adds new precision to the Allies' intensive bombing raids against Germany.
The tide of the war turns in the Allies' favor.
But Hitler continues to secretly develop destructive new weapons, and it's up to the Allies to find them before they can be unleashed.
May 1942.
While flying a reconnaissance mission over a remote island off the Baltic coast, something catches a pilot's eye.
It's an obscure place called Peenemünde.
STANLEY: He saw they were making an airfield.
Well, nothing attracts aerial intelligence like an airfield.
And the only thing there that attracted anybody's attention were the three big concrete and earth circles.
MOCKFORD: I think there was all sorts of conjecture as to what the three circles were.
HALSALL: As a PI looking at those in isolation, my immediate reaction would probably be to think that they might be something to do with sewage, actually.
NARRATOR: Nothing in the photos suggests an imminent threat.
EHLERS: So, given the pressing nature of other things that they were doing at the time, the photo interpreters shelved those photos in 1942.
NARRATOR: Nearly a year later, British intelligence bug a conversation between two captured German generals being held in a stately home in London.
EHLERS: The British overheard two German generals captured in North Africa talking about this rocket-- this future weapon that would soon be raining down on the British and might change the course of the war.
MAIOLO: One remarked to the other that something must have gone wrong with the rocket program because they couldn't hear the big bangs of rockets landing around them.
NARRATOR: The Spitfire spy planes scour Germany and northern France for evidence of rockets.
Thousands of photos are rushed back.
The interpreters look for anything out of the ordinary.
BRUGIONI: They were told to look for something queer, for a tube out of which could be squirted a missile.
To ask a photo interpreter to do an analysis of a missile site that has never seen one before was asking a lot.
HICK: You were trained to know what would be normal to look at, so you had to have a sense of anomalies.
STONE: And there's a certain amount of detective work in looking at clues.
I always felt it was like doing a gigantic jigsaw puzzle.
NARRATOR: They also scour through old photos for something they may have previously overlooked.
A photo interpreter spots what appears to be a tube in one of the mysterious circles photographed at Peenemünde a year earlier.
Now the real detective work begins.
STONE: All that was seen was a tube.
To see the initial image was one thing.
To work out what it was and what it could do was a very different one.
NARRATOR: 3D analysis reveals something extraordinary: a rocket.
This is absolutely great.
We've got here a photograph which shows two rockets.
MOCKFORD: It's a significant moment in history, without any question, when they saw this for the first time.
HALSALL: People, having looked at these, they said, "Well, how do they launch them?" And it was then that they started looking back over imagery and they eventually discovered the first one that was actually sticking up vertically and looked like a sort of big pole really, sticking up in the air.
We've marked up where that first one is.
WILLIAMS: Pretty hard to see, but HALSALL: Yeah.
You can see the shadow of it there.
Sometimes you can learn more from the shadow than you can from the object, because you'll see the shadow on the ground and you can measure it.
NARRATOR: The PIs determine that the rocket is an imposing 45 feet high.
And it appears to be fired from a standing position.
A number of gifted, really gifted analysts were able to make sense of what was really going on in Peenemünde, a very mysterious, very complex sort of jigsaw puzzle.
NARRATOR: But key members of the British government doubt the Germans have the technology to build rockets.
For them, this is science fiction.
Analysts need something more than stereoscopic images to convince the government that the threat is real.
The answer is the Wild machine, used in the Dambusters mission with great success.
From data provided from the Wild machines, analysts hope to build an accurate and detailed model of Peenemünde, allowing generals to clearly see the precise layout and dimensions of the rocket launch site.
MOCKFORD: In the machine, built into the optics, there's a floating dot.
The floating dot enables you to actually trace a contour or to measure precisely an object in length, width, and the height of an object.
NARRATOR: But there is a shortage of Wild machines in Britain.
One of the only places to get them is Switzerland.
A daring mission is launched to smuggle two new Wild machines through Nazi Germany to Sweden.
There, they are secretly loaded onto planes and flown to Britain, evading German fighters as they go.
The Wild machines, along with the 3D photos, provide the model makers with the measurements needed to bring Peenemünde to life.
Now stored in the British Imperial War Museum, this is the model they made in 1943.
HALSALL: Ah, right, so this is the one original surviving model of Peenemünde, then.
MOCKFORD: Yeah, and it's in very good condition.
HALSALL: This is the first ballistic missile test site ever in the world.
It's perfect in almost every detail.
NARRATOR: The model makes a strong impression on Winston Churchill and his war cabinet.
MOCKFORD: They could come and study this and it would have been accurate in every detail of measurement and so they would have been able to size the missile against the construction building and the engine test site here.
I don't think the scientists at that time had any idea.
In fact, there was a lot of skepticism about what it was.
I think this is the classic, "We can't do it, they can't do it," and that's one of the greatest intelligence mistakes anyone ever makes.
NARRATOR: Underestimating the Germans proves costly.
In October 1942, they make one of the great breakthroughs in military history: in secret, they successfully launch a rocket.
The weapon, called the V2, is a terrifying innovation.
Traveling at 3,500 miles per hour and armed with a one-ton warhead, it can hit targets up to 200 miles away.
And now Medmenham has strong evidence that Peenemünde is the home of this alarming new weapon.
The Nazis spent a lot of money in Peenemünde.
This was the biggest research center in the world between 1936 and 1945.
I think the Germans were far, far ahead of us in terms of missile technology.
They had some brilliant men.
NARRATOR: Among them is Wernher von Braun, who will become famous after the war as the architect of the Saturn V rocket that will eventually take man to the moon.
Hitler hoped that this big collection of new weapons that he was developing would be in place in time, somehow, to turn the tide.
The Nazis got, once again, hope, hope to win the war.
NARRATOR: Still, at this stage, the Allies aren't convinced the threat is real.
Spy planes continue looking for evidence of the Nazis' clandestine rocket program.
In Northern France, hundreds of miles away from Peenemünde, pilots photograph a strange facility.
BRUGIONI: They find bunkers, large bunkers.
The bunkers didn't have any particular unique shape that you could determine what was in them.
STANLEY: They were huge, monstrous concrete structures.
HICK: Obviously nobody knew what they were.
They were so strange.
NARRATOR: These bunkers become known to the PIs as the heavy sites.
The biggest of all is in a quarry in a village called Wizernes, just 25 miles from the English Channel, photographed here from just 100 feet above the site.
BRUGIONI: This photograph the most daring photograph of World War Two.
Here you can see the dome, but to fly into a quarry and pull up and get a photograph is just amazing.
I made about two runs over it and they opened up on me and the flak was so damn thick that I was diving, doing all sharp turns and everything and I went out the Channel and I settled down because I was a little shaken.
MOCKFORD: There you go, there's the not quite from the same angle, but it's pretty much the view that the Spitfire got when he flew his very low level recce; I mean a true, a true dicing sortie.
I mean, here you've got the entire early structural stages here with, obviously, all the scaffolding and woodwork going in for the laying of the concrete and so on.
Just a huge effort going into building something on the French coast which was within, you know, reasonable shot of London.
Everybody agreed this is way, way too much effort to be anything but nefarious.
And it's too far back from the coast to be part of the defense works.
NARRATOR: Analysts conclude it must be part of the Nazis' rocket program.
What they don't know is that the bunkers are designed to prepare and launch V2 rockets at England.
Major firms in Germany were building them.
They would manufacture the missile.
And not only that, but then they had rails outside, places where they could fire the missile.
NARRATOR: After a heated debate between Churchill and his war cabinet, the prime minister is finally convinced that the rocket threat is real.
HALSALL: Adding it to the other heavy sites and adding it to Peenemünde put it all together and said, "Well, safest thing is to bomb this lot into extinction, if possible.
" NARRATOR: On August 17 and 18, 1943, more than 500 bombers set off from Britain with one aim: the complete destruction of Peenemünde and the elimination of the German rocket threat.
EHLERS: They launched the first night precision bombardment raid against Peenemünde.
STANLEY: Air crew were told, "If you don't get this, you're going back again," and that's kind of chilling.
It certainly underlines the importance of it.
EHLERS: The British were developing a fairly effective bomber force that could, in fact, hit targets at night with pretty good effect.
Even though there was heavy flak, even though the Luftwaffe did respond with a certain number of aircraft, the British were able to get in to the target and they were able to do very severe damage.
NARRATOR: Detailed photos are taken after the raid to assess the damage.
EHLERS: The British bombing raid killed several of the most important scientists and it put the Germans again very firmly on notice that the British knew what they were up to.
HALSALL: Of course as soon as Peenemünde had been bombed, they had to think about the heavy sites.
So it was decided to bomb all those as well.
NARRATOR: Again, aerial photos are used to prepare for the bombing of these sites.
MOCKFORD: We're standing in this area, I think, now.
And on that photograph you can still see some remnants of the construction program, actually, but the dome is complete and hugely thick and effectively bomb-proof.
NARRATOR: The Allies come up with a solution to take out the well-fortified bunker: a new generation of ground-penetrating bombs, including the 12,000-pound Tall Boy.
John Bell took part in the raid of Wizernes.
BELL: The Tall Boy worked very well.
It was a very accurate weapon, quite a pleasure to drop, really.
On our aiming at Wizernes, all we had to see was a dome sitting on top of a hillside and that's really what we aimed at.
Fortunately, the one I dropped was instrumental in making the dome tilt to one side.
But it perhaps was fortunate that we didn't hit it because otherwise the bomb might well have bounced off.
MOCKFORD: The near misses did the damage, actually, because they were earthquake effect and they actually caused the whole site to, you know, sort of tilt a little bit.
BELL: We attacked it on several occasions and managed to put it out of action.
NARRATOR: The successful bombing of the heavy sites provides only a brief victory.
Pilot John Blyth soon discovers other strange new facilities in France.
BLYTH: The only thing you could really see was a ramp.
And they put them in these little groups of woods.
I think the first time, I spent a half-hour before I finally caught on how I could see them, and after that it got easier, but they were still very, very difficult to spot.
NARRATOR: For the team at Medmenham, identifying these mysterious sites becomes a major challenge.
What the PIs see through their stereoscopes is perplexing: wooded areas full of new buildings, all of weird shapes and sizes.
In addition to the ramps, there are buildings that look like skis turned on their sides.
They become known as the ski sites.
MOCKFORD: Looking at it from the air is one thing, but actually ground-checking it is fascinating.
HALSALL: Nobody could imagine what on earth you would build a building this shape for.
NARRATOR: Nearly 100 sites are identified, all similar to one another.
MOCKFORD: When these were first seen, they were a complete mystery.
Nobody actually knew what they were or what they were for.
And this has got the classic ski structure signatures on it, which became, of course, the giveaway.
HALSALL: Looking at these photographs makes you realize what a challenge it was for the PIs at that time.
There was a lot of searching in the dark, you might say.
NARRATOR: With vital pieces of the jigsaw puzzle missing, it's unclear what these sites are for.
But a PI spots something in a photograph of Peenemünde taken before it was bombed that may be linked to the ramps seen at the strange new sites.
STONE: You could see it was some sort of flying vehicle, but what sort of flying vehicle? A lot of work was involved in inferring from what could be seen from measurements, from experience, from thinking of what it could be and what it could do.
HICK: A whisper went round the whole station so we were all very well aware that this was something absolutely fantastically important.
MOCKFORD: It's just a small blur, really.
It's just a tiny cruciform shape sitting on a ramp very, very similar to the ramp over there.
And that, then, with the ramp and the sites they'd already witnessed began to put the story together, and they realized that the threat was almost certainly a small pilotless aircraft.
NARRATOR: From the blurred cross, the PI concludes that it's another top-secret German weapon called the V1.
MAIOLO: The Luftwaffe was interested in a flying bomb.
A cruise missile is what we would call it.
The weapon seemed to have the potential to, again, launch a devastating knockout blow attack against London.
NARRATOR: Analysis reveals that the strange ramps are part of a complicated system needed to fire the V1.
WARNER: They would start the engine and then this complex system of pipes and valves that you have at the back here, this is part of the chemical- induced steam catapult which forces a shuttle, a big sort of dumbbell-shaped piece of metal, through the tube connected to the V1, which then fires it with great speed up to 250 miles an hour, and off it goes.
STANLEY: Suddenly, all those strange structures in France meant something and now they knew those were the ramps that were going to launch the V1s.
NARRATOR: Using the Wild machine for more accurate and detailed readings, analysts determine where the Nazis are aiming the flying bombs.
They plotted the ramps, and they could see exactly where the V1s were headed: Southampton, Portsmouth, London.
NARRATOR: The timing cannot be worse for the Allies.
Plans are under way to invade France.
HICK: They were planning on the D-Day landings, and how was this going to affect those plans? NARRATOR: The team at Medmenham is helping to pave the way for the D-Day landings planned for summer 1944.
The operation will be jeopardized if the Germans launch the V1s on England's Channel ports.
STANLEY: If you could have had a couple of those V1s hit a troop ship EHLERS: The Germans had planned to launch up to 2,000 V1s a day.
HICK: It was vital that they attack them and wipe them out, otherwise it wouldn't have been possible to invade.
NARRATOR: The Allies must eliminate the V1 flying bomb threat.
They launch Operation Crossbow.
Thousands of missions drop tens of thousands of bombs on the V weapons' launch sites.
BLYTH: The heaviest bombing I ever saw.
You couldn't see much of anything, there were so many craters.
NARRATOR: The success of Operation Crossbow directly impacts the plans for D-Day.
STANLEY: If the bombers hadn't destroyed those sites, it's hard to tell what would have happened to the Normandy invasion.
It would have probably had to have been put off.
In the process of destroying those launch sites, they reduced the number of potential V1 launches by as much as 95%.
STONE: There's no doubt at all that the intensive bombing of the V1 sites must have prevented a substantial part of the intended attack from ever arriving.
It was vital to the mounting of the invasion.
NARRATOR: Now, Medmenham shifts its focus and resources to the D-Day invasion, identifying threats and looking for weaknesses in the German defenses.
Photographic reconnaissance allowed operational commanders to point their heavy bombers at the right targets.
BRUGIONI: This was a fantastic effort.
Hundreds of daily flights monitoring all the activities.
TAYLOR: On the Normandy landings, every platoon commander had photographs of where he was landing, where the mines were and where the obstacles were.
Everything was known.
NARRATOR: The Allies land on the beaches of Normandy in France on June 6, 1944.
Not one German V rocket is fired.
But the V1 threat is not eliminated as the Allies hoped.
STANLEY: The first V1 landed on London a week after we were ashore in Normandy.
NARRATOR: The V1 brings new terror to the streets of London.
It becomes known as the Doodlebug because of the sinister sound it makes.
It went pup, pup, pup, then suddenly stopped, and you hoped that you weren't under or anywhere near where it was going to drop.
NARRATOR: Thousands die.
The British fight back in unconventional ways.
BRUGIONI: Spitfires would fly alongside the V1s and then tipped their wings over so that they would crash.
NARRATOR: The team at Medmenham continues to try and identify the V1 launch sites.
But every time the sites are exposed, the Germans come up with new strategies, hiding their operations with camouflage and less conspicuous launch areas.
EHLERS: They developed very small sites and they would bring the missiles literally at the last possible minute, set up the missile, fuel it, launch it, and get out of there.
NARRATOR: The photo interpreters use 3D to find a needle in a haystack.
MOCKFORD: These were much, much harder to find.
This is an example in Holland.
It's at a sugar factory and the signatures that give away the site are actually very tentative.
There is scarring on the land, there is damage on a building roof and the ramp is almost impossible to see, is here, just tucked inside the building.
HALSALL: You see, that pattern we've got there of those scarrings were not something that's normal at all.
MOCKFORD: This shows the V1 taking off the ramp and the booster motor and the dolly that supported it are dropping off, and that's what you're seeing here, causing scarring.
NARRATOR: The findings allow Allied bombers to target these sites and limit the barrage against London, giving the ground forces time to destroy the remaining V1 sites as they fight their way across Northern France.
The Allies are confident that the threat is extinguished.
But in September 1944, a V2 rocket, thought to have been destroyed in the bombing raids of Peenemünde, crashes into West London.
MAIOLO: In the 1940s, it was a really advanced piece of equipment.
It was a liquid-fueled rocket, which meant you had a high energy output from the motor and a very light body so you could carry a large warhead a great distance.
It would, under its own power, fly in a trajectory for about 65 seconds.
Once the motor cut out, the rocket would turn to its target and fall in a ballistic trajectory and land with great force.
BRUGIONI: Defenses against the V1 were possible.
There was no defense against the V2.
Once they fired, they're gone.
The notion that you could be blown up by something before you even knew it was coming was always a bit alarming.
I was probably the first to see a V2 going up.
I was on my way to a target and suddenly, through the cloud came a vertical contrail.
And I thought, "Hey, that's funny.
" I thought, "It must be a rocket.
" I tried to take a photograph of this contrail, but I failed.
When I got back to base, I reported this, of course, but nobody else believed it, and it was called Taylor's Folly.
NARRATOR: All efforts turned to finding and destroying V2 launch sites.
BRUGIONI: This was a major problem because the V2 was mobile.
So you'd fly and think, "Dash, here it is, here's one, here's one," and you'd photograph it.
All they did was pour a big concrete slab and the trucks would come and they'd erect the rocket itself and refuel it, sitting on this concrete pad.
Then they'd fire it and drive off.
The whole thing about the missile system was shoot and scoot.
NARRATOR: With no fixed targets, Medmenham desperately looks for new ways to contain the threat.
MOCKFORD: What RAF Medmenham did at the time was they attacked the transport system, the type of vehicles they were using and all the supporting infrastructure that supported the V2, which made it an incredibly difficult challenge.
TAYLOR: The only way to stop the V2 in the end was the army, to overrun the launch sites, which is what they did in the end.
NARRATOR: Nearly two years after the discovery at Peenemünde, the V2 threat is over.
Hitler is on the brink of defeat.
When the Allies advance into Germany, they learn just how serious that threat was.
In April 1945, American troops discover a hidden weapons factory in the Harz Mountains in northern Germany.
Built deep underground after the bombing of Peenemünde, the Nazis force tens of thousands of slave workers to build V weapons.
EUGENE BLACK: I was selected for slave labor.
Entering the tunnel the place was lit up, massive it was.
I immediately thought, "Good God, we are going to be kept here and we're never going to see daylight again.
" The dust and the dampness it was unbelievable.
People either lost the will to live or just through the conditions, they couldn't cope with it and they perished.
There were dead bodies lying all over.
NARRATOR: Spy planes previously exposed the factory and the Dora labor camp, but there was little they could do.
STANLEY: When you put it underground, first of all it's devilish hard to bomb, and it's impossible to tell what's going on inside.
NARRATOR: The full horror of the camp is revealed when it is liberated by American troops.
The dead were stacked like cord wood.
Thousands of dead people were there that were the Dora inmates.
They weren't burying the dead; they were just stacking them outside the underground.
BLACK: We were robbed of our future, of our youth.
It's just unbelievable what we as humans are able to do to each other.
NARRATOR: An estimated 20,000 slave workers die building the Nazis' V weapons.
that helped thwart those weapons reunite at Medmenham.
It's going to dive-bomb us.
NARRATOR: In many ways, they are the unsung heroes of the war.
MOCKFORD: Without the unique qualities of the people who worked there, we would have been far worse off.
I think the war would have been extended, or could easily have been extended by a year or two.
They made a huge contribution.
HICK: When the war was over, in a very small way, I had contributed something of value to the war effort.
STONE: People were doing it for the sake of the job and because the job was worthwhile and because it was exciting and valuable and you could see the point of it.
BLYTH: It meant so much to me.
It meant so much to the rest of my life.
And I loved it.
The British and the Americans spent a good bit of money on reconnaissance platforms and cameras, but they got a huge payoff in the process.
Shortened Allied casualty lists dramatically.
TAYLOR: It's not really a war machine because photographs can't do any harm to anybody until we drop bombs on the Germans as a result of these photographs, which, of course, in the end won us the war.
BRUGIONI: All the people that worked at Medmenham, there's one word and that was dedication.
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Hitler's armies storm through Europe, crushing everything in their path.
Western Europe is on the brink of defeat.
The Allies turn to the iconic Spitfire to help change the course of the war.
Now, the fighter plane is not armed with weapons that kill, but with one that will keep them one step ahead of the Nazi war machine.
A surveillance camera.
British and American pilots fly dangerous missions to gather critical intelligence.
JOHN S.
BLYTH: My job was as a photo reconnaissance pilot.
It was a wonderful airplane to fly.
I loved it.
It had cameras, no guns.
NARRATOR: In a country house located 35 miles west of London, a team of brilliant minds analyzes the tens of millions of aerial photos taken during the war and recently declassified for the first time.
MIKE MOCKFORD: Nothing moved in Europe which we did not photograph, and it was utterly critical to the Allied success in the Second World War.
NARRATOR: The photo interpreters have a secret weapon to expose German secrets.
Using stereoscopes, they bring the Nazis' world to life in 3D.
DINO BRUGIONI: In 3D, the first thing, you can get height.
Also at the same time you can measure very effectively, too, the width.
NARRATOR: Using this technology, an obscure photograph reveals evidence of one of Hitler's most secretive and most lethal weapons programs.
MOCKFORD: In today's terminology, the V weapons were the first weapons of mass destruction.
NARRATOR: How did a handful of photo interpreters so far from the battlefields succeed in derailing Hitler's wonder weapons? BRUGIONI: Working night and day, they saved thousands and thousands of lives.
NARRATOR: "3D Spies of World War II," right now on NOVA.
Major funding for NOVA is provided by the following: Supporting NOVA and promoting public understanding of science.
And the Corporation for Public Broadcasting and by PBS viewers like you.
Additional funding from: Inspiring tomorrow's engineers and technologists.
NARRATOR: September 1939, Germany invades Poland and the Second World War is under way.
Adolf Hitler launches an all-out assault.
One European nation after another crumbles.
JOE MAIOLO: The German strategy was to win as quick a war as they possibly could.
NARRATOR: Britain is the last nation standing.
Just eight months after invading Poland, Hitler is poised for domination.
The battle for Europe unfolds in the skies over Britain.
Defeating German airpower falls to Britain's most advanced fighter plane, the Spitfire.
BLYTH: When I was in high school, the Battle of Britain was on, and the Spitfire was the only aircraft actually that could compete against the Germans.
NARRATOR: Nearly four months later, the Spitfire and her heroic pilots helped to win the Battle of Britain.
But the victory is short-lived.
The Germans begin a relentless nine-month bombing campaign against British cities.
The Blitz leaves more than 40,000 civilians dead.
To strike back at German cities, the Royal Air Force needs more accurate and up-to-date intelligence.
Aerial photographs are the key.
ROBERT EHLERS: Photographic reconnaissance was exceptionally important.
80% of British intelligence came from photo interpretation.
It allowed operational commanders to point their heavy bombers at the right targets.
NARRATOR: Once again, military leaders turn to the Spitfire.
Now, it will be armed not with guns, but with cameras.
The Spitfire is transformed from a killing machine into a spy plane, the Allies' eyes in the sky.
It is redesigned to fly faster, higher, and farther.
Retrofitting the Spitfires with the new cameras is not a simple task.
JIMMY TAYLOR: It had five cameras.
One was fitted under each wing here and two in the fuselage.
And these were vertical cameras.
The big ones were for the high level, of course, and the small ones were for the low level.
NARRATOR: The F52 camera, the most sophisticated of the day, is the weapon of choice.
With its large image format and lenses with longer focal lengths, it can take detailed photos like these from altitudes of up to 30,000 feet.
TAYLOR: The camera's here.
As you can see, it's a pretty big one, and that would have to be put through this hatch here and point down through one of these two portholes in the bottom of the fuselage.
NARRATOR: The missions take pilots deep into German territory.
There is a constant fear of being intercepted and shot down.
And at 30,000 feet, temperatures plummet to minus-50 degrees.
BLYTH: It was cold.
They bled off most of the warm air to heat the cameras to keep the film going.
Sometimes your knees you could hardly bend them or anything.
NARRATOR: Taking photos that are useful to intelligence analysts requires extraordinary skill.
When they found their target, they had to fly a level course because if they weren't flying straight and level, it distorted the pictures.
You would have to get right over the target, practically, and roll over and see the target and then bring the airplane around and level out and fly straight and level while the cameras were turning.
NARRATOR: Reconnaissance pilots take tens of millions of photographs during the war.
Many, only recently declassified, are kept here, at an archive in Edinburgh, Scotland.
Researcher Allan Williams is working with retired RAF Wing Commander Mike Mockford and Major Chris Halsall, both photo interpreters after the war, to track down the photos that helped defeat the Nazis.
MOCKFORD: Nothing moved in Europe which we did not photograph, and it was critical to the Allied success in the Second World War.
CHRIS HALSALL: Without air reconnaissance, it is difficult to imagine how we could have possibly achieved the results we did.
NARRATOR: The key to their success lies in a meticulous three-phase interpretation process that starts at the airfield.
TAYLOR: They would look at the photographs and if something needed immediate action, within 24 hours, say, where the army had to shell or the air force had to bomb some target NARRATOR: The photos are then rushed to a Royal Air Force base at Medmenham, a country estate 35 miles west of London.
TAYLOR: They'd send all the more important photographs to Medmenham because they had interpreters there, and there were 2,000 of these by the war's end, all specialized in different sections, and they would then identify whether there was something that could be bombed or attacked in the next week or so, which was phase two, or whether it was a long-term thing about the German war effort, and they contributed to the to phase three.
NARRATOR: Deciding which photos are priorities is critical.
The interpreters must decipher every last detail from the images.
But their analysis is only as good as the material they have to work with.
This is an aerial photo of the elite German battleship the Tirpitz.
MOCKFORD: You can see all the guns, you can see the crew on the deck, and nobody has moved.
I suspect the crew on the deck are probably stunned by the noise of the aircraft.
HALSALL: That photograph, what is acknowledged to be probably one of the closest-ever shots of a major German capital ship.
NARRATOR: But for analysts at Medmenham, photos taken at an oblique angle have limited value.
Instead, pilots must shoot the photos while looking straight down and from a much higher altitude.
MOCKFORD: The vertical photograph is your intelligence analysts' ideal: no hidden ground, easy to scale because it's like a map.
You really can see very clearly exactly what you've got down there.
NARRATOR: The vertical photos allow the interpreters to employ one of their greatest intelligence weapons: a stereoscope, which enables them to see in three dimensions.
Now, they expose details previously invisible, allowing them to accurately select their targets and assess damage after bombing raids.
For it to work, the pilots must take the photos in an overlapping sequence.
TAYLOR: We had to make sure that when they were viewed by the photo interpreters, each of these pictures overlapped the other by 60%, because everything on the photograph would then stand up in three dimensions.
NARRATOR: These two photos show a Norwegian fjord.
When overlapped under the stereoscope, the brain fuses them into one, creating the perception of depth, so the fjord appears in three dimensions.
The benefits are immediate.
This photo reveals what appears to be a German ship in the middle of the fjord.
MOCKFORD: The ship itself, with all its preparation for camouflage, is very unusual.
In fact, I think there's something exceedingly odd about this particular ship and the image, and you'd see this very clearly in three dimensions.
NARRATOR: 3D allows analysts to see something they wouldn't have seen otherwise: the true position of the ship concealed along the shoreline.
HALSALL: Going offshore, there is this decoy and boom combined where they've lashed together tires in the water, joined them all up together, and made them look like a ship floating in the water.
NARRATOR: The work at RAF Medmenham plays an increasingly vital role in the war effort, and the job of the photo interpreters, or PIs, requires the top minds.
EHLERS: It's stunning when you think about it, because the British had their pick of the very best people who could see things.
Photo interpreters had to have 20/20 vision.
STONE: They recruited a lot of academics, and particularly academics who were accustomed to being precise.
ELIZABETH HICK: A lot of them were recruited from Oxford and Cambridge: mathematicians, geologists, archaeologists.
NARRATOR: Interpreting photographs is not just an academic skill.
Finding hidden details requires a creative mind.
Once the U.
S.
enters the war in 1941, Medmenham looks to Hollywood for talent.
Walt Disney legend and imagineer Xavier Atencio, who later helps create the Pirates of the Caribbean, is part of a large American contingent at Medmenham.
XAVIER ATENCIO: I was assigned to airfields.
That's how I became an expert on airfields.
We had quite a few artists in our unit because we had an eye for detail.
MARGARET HURLEY: A lot of them were very handpicked.
Yes, I wasn't.
A lot of them were.
NARRATOR: By 1942, with a brilliant team at Medmenham in place, the RAF plans a bold new strategy.
Aerial intelligence is key in identifying targets.
Their top priority is to figure out a way to strike a crippling blow to Hitler's war machine.
They plan to raid dams in the Ruhr Valley, the source of the Nazis' hydroelectric power supply and the heart of their weapons industry.
Located deep in the heartland of Germany, these are not easy targets.
Success depends on detailed information about the dams.
MOCKFORD: Medmenham played a huge role.
They prepared most all the pre-targeting information.
They designed and built the models on which much of the planning was done for the dams' raid.
Before the dams' raid took place, Medmenham were critical in telling the bomber commands-- the squadron and the bomber command-- when the dams had sufficient water in to make the bomb effective, because they had to wait until the water level rose to a certain point.
NARRATOR: The Spitfire images alone will not be enough for such a precision bombing mission.
A state-of-the-art machine called the Wild is used to make precise measurements from aerial photos.
EHLERS: It was a photogrammetric machine that could measure distances, so they knew not only how big an object was, but what the distance was between objects.
They were able, very precisely, to know where to put their crosshairs.
NARRATOR: Within hours of the Dambusters raid, spy planes assess the damage.
The dams are breached and the Ruhr valley is flooded, disrupting vital German industries.
MOCKFORD: The air ministry phoned Medmenham and spoke to the man who was doing the damage assessment and said to him in a very excited voice, apparently, "What's it like, what's it like, how big is the breach?" you know.
And they were really hanging on every word and he gave him the answer over the phone: they breached two dams.
There was terrible devastation and awful loss of life, but, um we were fighting for our life.
NARRATOR: 3D aerial photography adds new precision to the Allies' intensive bombing raids against Germany.
The tide of the war turns in the Allies' favor.
But Hitler continues to secretly develop destructive new weapons, and it's up to the Allies to find them before they can be unleashed.
May 1942.
While flying a reconnaissance mission over a remote island off the Baltic coast, something catches a pilot's eye.
It's an obscure place called Peenemünde.
STANLEY: He saw they were making an airfield.
Well, nothing attracts aerial intelligence like an airfield.
And the only thing there that attracted anybody's attention were the three big concrete and earth circles.
MOCKFORD: I think there was all sorts of conjecture as to what the three circles were.
HALSALL: As a PI looking at those in isolation, my immediate reaction would probably be to think that they might be something to do with sewage, actually.
NARRATOR: Nothing in the photos suggests an imminent threat.
EHLERS: So, given the pressing nature of other things that they were doing at the time, the photo interpreters shelved those photos in 1942.
NARRATOR: Nearly a year later, British intelligence bug a conversation between two captured German generals being held in a stately home in London.
EHLERS: The British overheard two German generals captured in North Africa talking about this rocket-- this future weapon that would soon be raining down on the British and might change the course of the war.
MAIOLO: One remarked to the other that something must have gone wrong with the rocket program because they couldn't hear the big bangs of rockets landing around them.
NARRATOR: The Spitfire spy planes scour Germany and northern France for evidence of rockets.
Thousands of photos are rushed back.
The interpreters look for anything out of the ordinary.
BRUGIONI: They were told to look for something queer, for a tube out of which could be squirted a missile.
To ask a photo interpreter to do an analysis of a missile site that has never seen one before was asking a lot.
HICK: You were trained to know what would be normal to look at, so you had to have a sense of anomalies.
STONE: And there's a certain amount of detective work in looking at clues.
I always felt it was like doing a gigantic jigsaw puzzle.
NARRATOR: They also scour through old photos for something they may have previously overlooked.
A photo interpreter spots what appears to be a tube in one of the mysterious circles photographed at Peenemünde a year earlier.
Now the real detective work begins.
STONE: All that was seen was a tube.
To see the initial image was one thing.
To work out what it was and what it could do was a very different one.
NARRATOR: 3D analysis reveals something extraordinary: a rocket.
This is absolutely great.
We've got here a photograph which shows two rockets.
MOCKFORD: It's a significant moment in history, without any question, when they saw this for the first time.
HALSALL: People, having looked at these, they said, "Well, how do they launch them?" And it was then that they started looking back over imagery and they eventually discovered the first one that was actually sticking up vertically and looked like a sort of big pole really, sticking up in the air.
We've marked up where that first one is.
WILLIAMS: Pretty hard to see, but HALSALL: Yeah.
You can see the shadow of it there.
Sometimes you can learn more from the shadow than you can from the object, because you'll see the shadow on the ground and you can measure it.
NARRATOR: The PIs determine that the rocket is an imposing 45 feet high.
And it appears to be fired from a standing position.
A number of gifted, really gifted analysts were able to make sense of what was really going on in Peenemünde, a very mysterious, very complex sort of jigsaw puzzle.
NARRATOR: But key members of the British government doubt the Germans have the technology to build rockets.
For them, this is science fiction.
Analysts need something more than stereoscopic images to convince the government that the threat is real.
The answer is the Wild machine, used in the Dambusters mission with great success.
From data provided from the Wild machines, analysts hope to build an accurate and detailed model of Peenemünde, allowing generals to clearly see the precise layout and dimensions of the rocket launch site.
MOCKFORD: In the machine, built into the optics, there's a floating dot.
The floating dot enables you to actually trace a contour or to measure precisely an object in length, width, and the height of an object.
NARRATOR: But there is a shortage of Wild machines in Britain.
One of the only places to get them is Switzerland.
A daring mission is launched to smuggle two new Wild machines through Nazi Germany to Sweden.
There, they are secretly loaded onto planes and flown to Britain, evading German fighters as they go.
The Wild machines, along with the 3D photos, provide the model makers with the measurements needed to bring Peenemünde to life.
Now stored in the British Imperial War Museum, this is the model they made in 1943.
HALSALL: Ah, right, so this is the one original surviving model of Peenemünde, then.
MOCKFORD: Yeah, and it's in very good condition.
HALSALL: This is the first ballistic missile test site ever in the world.
It's perfect in almost every detail.
NARRATOR: The model makes a strong impression on Winston Churchill and his war cabinet.
MOCKFORD: They could come and study this and it would have been accurate in every detail of measurement and so they would have been able to size the missile against the construction building and the engine test site here.
I don't think the scientists at that time had any idea.
In fact, there was a lot of skepticism about what it was.
I think this is the classic, "We can't do it, they can't do it," and that's one of the greatest intelligence mistakes anyone ever makes.
NARRATOR: Underestimating the Germans proves costly.
In October 1942, they make one of the great breakthroughs in military history: in secret, they successfully launch a rocket.
The weapon, called the V2, is a terrifying innovation.
Traveling at 3,500 miles per hour and armed with a one-ton warhead, it can hit targets up to 200 miles away.
And now Medmenham has strong evidence that Peenemünde is the home of this alarming new weapon.
The Nazis spent a lot of money in Peenemünde.
This was the biggest research center in the world between 1936 and 1945.
I think the Germans were far, far ahead of us in terms of missile technology.
They had some brilliant men.
NARRATOR: Among them is Wernher von Braun, who will become famous after the war as the architect of the Saturn V rocket that will eventually take man to the moon.
Hitler hoped that this big collection of new weapons that he was developing would be in place in time, somehow, to turn the tide.
The Nazis got, once again, hope, hope to win the war.
NARRATOR: Still, at this stage, the Allies aren't convinced the threat is real.
Spy planes continue looking for evidence of the Nazis' clandestine rocket program.
In Northern France, hundreds of miles away from Peenemünde, pilots photograph a strange facility.
BRUGIONI: They find bunkers, large bunkers.
The bunkers didn't have any particular unique shape that you could determine what was in them.
STANLEY: They were huge, monstrous concrete structures.
HICK: Obviously nobody knew what they were.
They were so strange.
NARRATOR: These bunkers become known to the PIs as the heavy sites.
The biggest of all is in a quarry in a village called Wizernes, just 25 miles from the English Channel, photographed here from just 100 feet above the site.
BRUGIONI: This photograph the most daring photograph of World War Two.
Here you can see the dome, but to fly into a quarry and pull up and get a photograph is just amazing.
I made about two runs over it and they opened up on me and the flak was so damn thick that I was diving, doing all sharp turns and everything and I went out the Channel and I settled down because I was a little shaken.
MOCKFORD: There you go, there's the not quite from the same angle, but it's pretty much the view that the Spitfire got when he flew his very low level recce; I mean a true, a true dicing sortie.
I mean, here you've got the entire early structural stages here with, obviously, all the scaffolding and woodwork going in for the laying of the concrete and so on.
Just a huge effort going into building something on the French coast which was within, you know, reasonable shot of London.
Everybody agreed this is way, way too much effort to be anything but nefarious.
And it's too far back from the coast to be part of the defense works.
NARRATOR: Analysts conclude it must be part of the Nazis' rocket program.
What they don't know is that the bunkers are designed to prepare and launch V2 rockets at England.
Major firms in Germany were building them.
They would manufacture the missile.
And not only that, but then they had rails outside, places where they could fire the missile.
NARRATOR: After a heated debate between Churchill and his war cabinet, the prime minister is finally convinced that the rocket threat is real.
HALSALL: Adding it to the other heavy sites and adding it to Peenemünde put it all together and said, "Well, safest thing is to bomb this lot into extinction, if possible.
" NARRATOR: On August 17 and 18, 1943, more than 500 bombers set off from Britain with one aim: the complete destruction of Peenemünde and the elimination of the German rocket threat.
EHLERS: They launched the first night precision bombardment raid against Peenemünde.
STANLEY: Air crew were told, "If you don't get this, you're going back again," and that's kind of chilling.
It certainly underlines the importance of it.
EHLERS: The British were developing a fairly effective bomber force that could, in fact, hit targets at night with pretty good effect.
Even though there was heavy flak, even though the Luftwaffe did respond with a certain number of aircraft, the British were able to get in to the target and they were able to do very severe damage.
NARRATOR: Detailed photos are taken after the raid to assess the damage.
EHLERS: The British bombing raid killed several of the most important scientists and it put the Germans again very firmly on notice that the British knew what they were up to.
HALSALL: Of course as soon as Peenemünde had been bombed, they had to think about the heavy sites.
So it was decided to bomb all those as well.
NARRATOR: Again, aerial photos are used to prepare for the bombing of these sites.
MOCKFORD: We're standing in this area, I think, now.
And on that photograph you can still see some remnants of the construction program, actually, but the dome is complete and hugely thick and effectively bomb-proof.
NARRATOR: The Allies come up with a solution to take out the well-fortified bunker: a new generation of ground-penetrating bombs, including the 12,000-pound Tall Boy.
John Bell took part in the raid of Wizernes.
BELL: The Tall Boy worked very well.
It was a very accurate weapon, quite a pleasure to drop, really.
On our aiming at Wizernes, all we had to see was a dome sitting on top of a hillside and that's really what we aimed at.
Fortunately, the one I dropped was instrumental in making the dome tilt to one side.
But it perhaps was fortunate that we didn't hit it because otherwise the bomb might well have bounced off.
MOCKFORD: The near misses did the damage, actually, because they were earthquake effect and they actually caused the whole site to, you know, sort of tilt a little bit.
BELL: We attacked it on several occasions and managed to put it out of action.
NARRATOR: The successful bombing of the heavy sites provides only a brief victory.
Pilot John Blyth soon discovers other strange new facilities in France.
BLYTH: The only thing you could really see was a ramp.
And they put them in these little groups of woods.
I think the first time, I spent a half-hour before I finally caught on how I could see them, and after that it got easier, but they were still very, very difficult to spot.
NARRATOR: For the team at Medmenham, identifying these mysterious sites becomes a major challenge.
What the PIs see through their stereoscopes is perplexing: wooded areas full of new buildings, all of weird shapes and sizes.
In addition to the ramps, there are buildings that look like skis turned on their sides.
They become known as the ski sites.
MOCKFORD: Looking at it from the air is one thing, but actually ground-checking it is fascinating.
HALSALL: Nobody could imagine what on earth you would build a building this shape for.
NARRATOR: Nearly 100 sites are identified, all similar to one another.
MOCKFORD: When these were first seen, they were a complete mystery.
Nobody actually knew what they were or what they were for.
And this has got the classic ski structure signatures on it, which became, of course, the giveaway.
HALSALL: Looking at these photographs makes you realize what a challenge it was for the PIs at that time.
There was a lot of searching in the dark, you might say.
NARRATOR: With vital pieces of the jigsaw puzzle missing, it's unclear what these sites are for.
But a PI spots something in a photograph of Peenemünde taken before it was bombed that may be linked to the ramps seen at the strange new sites.
STONE: You could see it was some sort of flying vehicle, but what sort of flying vehicle? A lot of work was involved in inferring from what could be seen from measurements, from experience, from thinking of what it could be and what it could do.
HICK: A whisper went round the whole station so we were all very well aware that this was something absolutely fantastically important.
MOCKFORD: It's just a small blur, really.
It's just a tiny cruciform shape sitting on a ramp very, very similar to the ramp over there.
And that, then, with the ramp and the sites they'd already witnessed began to put the story together, and they realized that the threat was almost certainly a small pilotless aircraft.
NARRATOR: From the blurred cross, the PI concludes that it's another top-secret German weapon called the V1.
MAIOLO: The Luftwaffe was interested in a flying bomb.
A cruise missile is what we would call it.
The weapon seemed to have the potential to, again, launch a devastating knockout blow attack against London.
NARRATOR: Analysis reveals that the strange ramps are part of a complicated system needed to fire the V1.
WARNER: They would start the engine and then this complex system of pipes and valves that you have at the back here, this is part of the chemical- induced steam catapult which forces a shuttle, a big sort of dumbbell-shaped piece of metal, through the tube connected to the V1, which then fires it with great speed up to 250 miles an hour, and off it goes.
STANLEY: Suddenly, all those strange structures in France meant something and now they knew those were the ramps that were going to launch the V1s.
NARRATOR: Using the Wild machine for more accurate and detailed readings, analysts determine where the Nazis are aiming the flying bombs.
They plotted the ramps, and they could see exactly where the V1s were headed: Southampton, Portsmouth, London.
NARRATOR: The timing cannot be worse for the Allies.
Plans are under way to invade France.
HICK: They were planning on the D-Day landings, and how was this going to affect those plans? NARRATOR: The team at Medmenham is helping to pave the way for the D-Day landings planned for summer 1944.
The operation will be jeopardized if the Germans launch the V1s on England's Channel ports.
STANLEY: If you could have had a couple of those V1s hit a troop ship EHLERS: The Germans had planned to launch up to 2,000 V1s a day.
HICK: It was vital that they attack them and wipe them out, otherwise it wouldn't have been possible to invade.
NARRATOR: The Allies must eliminate the V1 flying bomb threat.
They launch Operation Crossbow.
Thousands of missions drop tens of thousands of bombs on the V weapons' launch sites.
BLYTH: The heaviest bombing I ever saw.
You couldn't see much of anything, there were so many craters.
NARRATOR: The success of Operation Crossbow directly impacts the plans for D-Day.
STANLEY: If the bombers hadn't destroyed those sites, it's hard to tell what would have happened to the Normandy invasion.
It would have probably had to have been put off.
In the process of destroying those launch sites, they reduced the number of potential V1 launches by as much as 95%.
STONE: There's no doubt at all that the intensive bombing of the V1 sites must have prevented a substantial part of the intended attack from ever arriving.
It was vital to the mounting of the invasion.
NARRATOR: Now, Medmenham shifts its focus and resources to the D-Day invasion, identifying threats and looking for weaknesses in the German defenses.
Photographic reconnaissance allowed operational commanders to point their heavy bombers at the right targets.
BRUGIONI: This was a fantastic effort.
Hundreds of daily flights monitoring all the activities.
TAYLOR: On the Normandy landings, every platoon commander had photographs of where he was landing, where the mines were and where the obstacles were.
Everything was known.
NARRATOR: The Allies land on the beaches of Normandy in France on June 6, 1944.
Not one German V rocket is fired.
But the V1 threat is not eliminated as the Allies hoped.
STANLEY: The first V1 landed on London a week after we were ashore in Normandy.
NARRATOR: The V1 brings new terror to the streets of London.
It becomes known as the Doodlebug because of the sinister sound it makes.
It went pup, pup, pup, then suddenly stopped, and you hoped that you weren't under or anywhere near where it was going to drop.
NARRATOR: Thousands die.
The British fight back in unconventional ways.
BRUGIONI: Spitfires would fly alongside the V1s and then tipped their wings over so that they would crash.
NARRATOR: The team at Medmenham continues to try and identify the V1 launch sites.
But every time the sites are exposed, the Germans come up with new strategies, hiding their operations with camouflage and less conspicuous launch areas.
EHLERS: They developed very small sites and they would bring the missiles literally at the last possible minute, set up the missile, fuel it, launch it, and get out of there.
NARRATOR: The photo interpreters use 3D to find a needle in a haystack.
MOCKFORD: These were much, much harder to find.
This is an example in Holland.
It's at a sugar factory and the signatures that give away the site are actually very tentative.
There is scarring on the land, there is damage on a building roof and the ramp is almost impossible to see, is here, just tucked inside the building.
HALSALL: You see, that pattern we've got there of those scarrings were not something that's normal at all.
MOCKFORD: This shows the V1 taking off the ramp and the booster motor and the dolly that supported it are dropping off, and that's what you're seeing here, causing scarring.
NARRATOR: The findings allow Allied bombers to target these sites and limit the barrage against London, giving the ground forces time to destroy the remaining V1 sites as they fight their way across Northern France.
The Allies are confident that the threat is extinguished.
But in September 1944, a V2 rocket, thought to have been destroyed in the bombing raids of Peenemünde, crashes into West London.
MAIOLO: In the 1940s, it was a really advanced piece of equipment.
It was a liquid-fueled rocket, which meant you had a high energy output from the motor and a very light body so you could carry a large warhead a great distance.
It would, under its own power, fly in a trajectory for about 65 seconds.
Once the motor cut out, the rocket would turn to its target and fall in a ballistic trajectory and land with great force.
BRUGIONI: Defenses against the V1 were possible.
There was no defense against the V2.
Once they fired, they're gone.
The notion that you could be blown up by something before you even knew it was coming was always a bit alarming.
I was probably the first to see a V2 going up.
I was on my way to a target and suddenly, through the cloud came a vertical contrail.
And I thought, "Hey, that's funny.
" I thought, "It must be a rocket.
" I tried to take a photograph of this contrail, but I failed.
When I got back to base, I reported this, of course, but nobody else believed it, and it was called Taylor's Folly.
NARRATOR: All efforts turned to finding and destroying V2 launch sites.
BRUGIONI: This was a major problem because the V2 was mobile.
So you'd fly and think, "Dash, here it is, here's one, here's one," and you'd photograph it.
All they did was pour a big concrete slab and the trucks would come and they'd erect the rocket itself and refuel it, sitting on this concrete pad.
Then they'd fire it and drive off.
The whole thing about the missile system was shoot and scoot.
NARRATOR: With no fixed targets, Medmenham desperately looks for new ways to contain the threat.
MOCKFORD: What RAF Medmenham did at the time was they attacked the transport system, the type of vehicles they were using and all the supporting infrastructure that supported the V2, which made it an incredibly difficult challenge.
TAYLOR: The only way to stop the V2 in the end was the army, to overrun the launch sites, which is what they did in the end.
NARRATOR: Nearly two years after the discovery at Peenemünde, the V2 threat is over.
Hitler is on the brink of defeat.
When the Allies advance into Germany, they learn just how serious that threat was.
In April 1945, American troops discover a hidden weapons factory in the Harz Mountains in northern Germany.
Built deep underground after the bombing of Peenemünde, the Nazis force tens of thousands of slave workers to build V weapons.
EUGENE BLACK: I was selected for slave labor.
Entering the tunnel the place was lit up, massive it was.
I immediately thought, "Good God, we are going to be kept here and we're never going to see daylight again.
" The dust and the dampness it was unbelievable.
People either lost the will to live or just through the conditions, they couldn't cope with it and they perished.
There were dead bodies lying all over.
NARRATOR: Spy planes previously exposed the factory and the Dora labor camp, but there was little they could do.
STANLEY: When you put it underground, first of all it's devilish hard to bomb, and it's impossible to tell what's going on inside.
NARRATOR: The full horror of the camp is revealed when it is liberated by American troops.
The dead were stacked like cord wood.
Thousands of dead people were there that were the Dora inmates.
They weren't burying the dead; they were just stacking them outside the underground.
BLACK: We were robbed of our future, of our youth.
It's just unbelievable what we as humans are able to do to each other.
NARRATOR: An estimated 20,000 slave workers die building the Nazis' V weapons.
that helped thwart those weapons reunite at Medmenham.
It's going to dive-bomb us.
NARRATOR: In many ways, they are the unsung heroes of the war.
MOCKFORD: Without the unique qualities of the people who worked there, we would have been far worse off.
I think the war would have been extended, or could easily have been extended by a year or two.
They made a huge contribution.
HICK: When the war was over, in a very small way, I had contributed something of value to the war effort.
STONE: People were doing it for the sake of the job and because the job was worthwhile and because it was exciting and valuable and you could see the point of it.
BLYTH: It meant so much to me.
It meant so much to the rest of my life.
And I loved it.
The British and the Americans spent a good bit of money on reconnaissance platforms and cameras, but they got a huge payoff in the process.
Shortened Allied casualty lists dramatically.
TAYLOR: It's not really a war machine because photographs can't do any harm to anybody until we drop bombs on the Germans as a result of these photographs, which, of course, in the end won us the war.
BRUGIONI: All the people that worked at Medmenham, there's one word and that was dedication.
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