(airplane engine roaring) (Dan) In spring, 1943... (panting, gunfire) ...133 young men set out on the most daring and ingenious bombing raid in history... (dramatic music) ...to destroy the great dams of Germany using bombs that bounce.

Look at the way it's skipping across the surface of the water there.

(Dan) If successful, they'll deal a hammer blow to the Nazi war effort.

(cheering) They're led by this man: Guy Gibson.

He's only 24, but he's already one of the most famous and highly decorated pilots in the world.

♪ I'm Dan Snow, and over three programs, I'm charting the nail-biting countdown to the mission.

In less than two months, 617 will be the most famous squadron number in RAF history.

Last time I revealed how, in just 60 days, the revolutionary new weapon was perfected... (bomb strikes water) And how the aircrew were trained to carry out the near impossible: to fly just 60 feet above the ground at night.

(airplane engine roaring) This time, I continue the story as they set out on the perilous raid itself... (airplane engine humming) ...and reveal how, despite tragedy... Barlow and his six-man crew are killed instantly.

...and disaster...

He pulls his own ripcord and throws his parachute out as a bundle and hops out after it.

They refuse to give up as they struggle to overcome the near impossible.

(machine guns fire) This is the story of the single mission that can change the course of the Second World War.

(bomb strikes water) These are the dambusters.

♪ (tense music) ♪ RAF Scampton, Lincolnshire.

♪ It's Sunday, the 16th of May, 1943.

And as the sun sets, the crews of 19 Lancaster bombers are preparing to take off on one of the most difficult missions of the Second World War... ♪ ...to attack the dams of Germany.

(airplane propellers whirring) But it almost begins with disaster.

That evening, the ground crews leave these hangars to watch the first of the Lancasters rumbling up this grass runway and into the dusk sky, the four Merlin engines roaring at full power.

(airplane engine humming) For secrecy, the ground crew have been told this is just another training mission.

But these are the men who'd earlier in the day loaded a massive four-ton bouncing bomb onto each of the aircraft.

♪ So they know, this time, it's for real.

(airplane engine sputtering) (grim music) ♪ As they watch, the ground crew hold their breath.

They notice that one of the Lancasters, codenamed E for Easy, is taking far longer than normal to take off.

(airplane engine humming) At the controls, 32-year-old Australian pilot Norman Barlow is struggling to get his aircraft off the ground due to the massive weight of the bouncing bomb.

(airplane engine humming) As he hurtles towards the perimeter fence, he has to use all his strength to haul back on the control column.

(airplane engine roaring) ♪ He gets his plane into the air just in time.

♪ And there's still another 400 miles to the target.

♪ 11 minutes later, three more Lancasters take off together.

At the controls of one is the mission commander, Guy Gibson.

(soft, tense music) They also struggle to get airborne.

But fortunately, they make it up safely, as do all the other bombers.

♪ (airplane engines humming) Despite the intense training and preparation, none of the 133 aircrew knew exactly what was in store for them.

But they'd soon find out.

Within an hour, the men of 617 Squadron were under heavy enemy fire.

♪ The 19 bomber crews are attacking the German dams in three waves.

The first wave of nine is led by Guy Gibson.

They're taking a southerly route across Holland to strike the primary target: the Möhne Dam.

If successful, they'll fly on to attack the Eder Dam.

The second wave of five aircraft is taking a more northerly route and bombing the Sorpe Dam.

A third, reserve wave of five aircraft will take off later.

(dramatic music) ♪ About 20 minutes after takeoff, the lead aircraft reach the English Coast, then drop down to wave-top height.

First over the North Sea is the aircraft W for Willie, part of the northern wave headed to the Sorpe Dam.

It's piloted by Les Munro, a 24-year-old sheep farmer's son from rural New Zealand.

He's flying on the edge of what's possible.

(Dr. Nubia) The pilots had to maintain radio silence.

They had to fly at a low altitude to avoid radar.

If they were heard or they were seen, the Germans would scramble fighter pilots and fighter aircraft.

And they would shoot those Lancaster bombers out of the sky.

(airplane engine humming) Crossing the North Sea was an epic in itself, because they were doing it at such a low level.

And you only needed the slightest lapse of concentration and you were in the drink.

(tense music) (Dan) The seven aircrew in Les Munro's Lancaster each have a critical role.

♪ As Munro approaches the enemy coast, he knows it's the skill of his Scottish navigator, Francis Rumbles, that will keep them alive.

♪ (Sir Hastings) If you just had a bit of a variation of wind speed, your navigator's a bit off course, then suddenly you find yourself over a German flak battery and being shot to pieces.

♪ (Dan) It's nearly 11:00 p.m., and the northerly wind is stronger than forecast.

Les Munro's experienced crew corrects for the extra drift.

And they cross the Dutch coast over the island of Vlieland as planned.

(airplane engine roaring) As he skims over the sand dunes, Munro looks to the right and he sees a burst of anti-aircraft flak followed by a huge explosion.

(explosion) He realizes that one of the other aircraft must have been blown too far to the south, strayed over a heavily defended island... (explosion) And paid a terrible price.

(solemn music) It's flown by Vernon Byers.

It's only Byers' sixth mission, and he's the squadron's least experienced pilot.

♪ His bouncing bomb is hit and explodes.

♪ Byers and his entire crew are killed.

♪ Then Munro hears a crack behind him, and his headphones go dead.

The island that he's just correctly over-flown was supposed to be undefended, but it wasn't.

Now, shells rip through his aircraft.

(machine gun fire) (dramatic music) One severs their intercom and radio cables.

(machine gun fire) There's no way they can continue the mission without being able to communicate.

♪ Then, as Munro is forced to turn for home, a third Lancaster hits trouble.

(airplane engine roaring) Geoff Rice, flying H for Harry, misjudges his height over the sea.

In the rear turret, his gunner, Sergeant Burns, feels a violent jolt and is suddenly submerged up to his waist in sea water!

It drains away slowly as the plane climbs.

But as he turns around to take stock, he looks forward, and he sees that the upkeep bouncing bomb isn't there.

(airplane engine humming) As they'd clipped the sea, their bomb had been ripped off.

Miraculously, they can still fly, but with no bomb, H for Harry also begins the journey home.

(airplane engine humming) Within just a few minutes of the first three aircraft reaching the enemy coast, two are returning home damaged and one has been destroyed.

The remaining 16 crews now face hundreds of miles of low-level flying above occupied Europe before they even reach the dams.

(panting) And not all of them will return.

(panting) (tense music) ♪ 617 Squadron's Commander, Guy Gibson, is approaching the Dutch coast.

(airplane engines humming) Flying in formation with him are Hoppy Hopgood in M for Mother and Mick Martin in P for Popsie.

(airplane engine humming) These three are heading to attack the main target, the Möhne Dam.

♪ They also experience strong winds and are blown south.

♪ As they sweep across the enemy coast at less than 50 feet, they fly straight into a heavily defended area.

♪ Hopgood's rear gunner, Tony Burcher, is thinking about his fiancée.

They're due to marry in just a few weeks.

♪ (gunfire) He's jolted back to reality as his aircraft is caught in enemy searchlights.

(dramatic music) Hopgood weaves violently to avoid the anti-aircraft fire arcing up towards them.

(muffled gunfire) Thrown around in his rear turret, just a few feet above the ground, Burcher is convinced that they're going to crash.

♪ Then suddenly, above his head whizzes a high-voltage electricity cable and disappears off into the distance.

Hopgood throws the plane into a climb.

"Right under the bloody things!"

shouts the front gunner on the intercom.

Hopgood replies, cool as anything, "Sorry about that."

♪ (airplane engine roaring) ♪ Gibson, Hopgood, and Martin amazingly thunder on unscathed... ♪ ...skimming over the trees and rooftops of Nazi-occupied Holland.

(airplane engine humming) (soft music) (birds chirping) ♪ As Gibson crosses the enemy coastline, Barnes Wallis, the designer of the bouncing bomb, is arriving at the headquarters of Bomber Command's 5 Group at St. Vincent's Hall, Grantham.

♪ Here, Wallis joins the boss of bomber command, Sir Arthur Harris.

The control room was on this spot, just outside that window, but it's since been demolished.

♪ They nervously wait for the first radio messages from the bombers, who'll only break radio silence once the attack begins.

♪ (Victoria) Back at the operations room in Grantham, you could cut the tension with a knife.

You had Wallis.

You had Harris.

You had all of these top personnel listening in, very, very nervously, to the radio.

And of course, there wasn't any communication as the Lancasters flew out.

So it really was this tense bubble of not knowing which way this raid was going to go.

♪ (Dan) Barnes Wallis paces continuously up and down.

Only that morning, he'd seen the faces of the young men for the first time.

Young men that were now risking their lives to execute his plan to destroy the dams.

He didn't know, of course, thanks to radio silence.

But by now, seven of those young men are already dead.

♪ (soft, tense music) ♪ The lead bombers are now just 25 minutes from their target.

(airplane engine humming) The first to cross into Germany itself is E for Easy, flown by Norman Barlow, the son of a wealthy, though rather shady, Australian businessman.

♪ It's one of only two planes remaining from the five who should be attacking the Sorpe Dam.

(airplane engine humming) ♪ Just moments after crossing the border at low level, E for Easy crashes into the very top of a 100,000-volt electricity pylon, bursts into flames, and crashes in a field.

Barlow and his six-man crew are killed instantly.

♪ Their bouncing bomb somehow survives the crash intact.

♪ No one realizes it yet, but the Germans are now in possession of Britain's new top-secret weapon.

♪ (dramatic music) Only one aircraft from the northern Sorpe Dam wave now remains, flown by American pilot Joe McCarthy.

He and his crew have no idea they're flying to the dam alone.

♪ (soft, tense music) To the south, the nine aircraft led by Guy Gibson and Hoppy Hopgood are enjoying a relatively uneventful flight across Holland.

♪ But then they cross the German border.

(dramatic music) ♪ In the lead are Gibson and Hopgood.

As they reach the Rhine, they discover they've strayed off course by six miles due to a mistake by the navigator.

♪ (man speaking indistinctly) Now, they're dangerously close to one of the thickest belts of anti-aircraft guns in Germany, protecting the Reich's industrial heartland, the Ruhr valley.

♪ Hopgood's rear gunner, Tony Burcher, is briefly blinded as searchlights illuminate the aircraft.

Then it's peppered from nose to tail by anti-aircraft fire.

He's wounded in the groin and the stomach, but just lightly, and he's able to continue returning fire on the searchlights.

(weapon clinking) The wireless operator suffers a terrible injury to his leg, and the front gunner is killed.

(gunfire) Hopgood is also wounded.

Despite blood pouring from a cut to his head, he manages to shut down the left outer engine, which has caught fire.

♪ Over the intercom here in the rear turret, Burcher hears the flight engineer shout, "Christ, look at all that blood!"

Then he hears Hopgood's calm reply: "Carry on, and don't worry.

I'm okay."

Astonishingly, they don't turn back but limp on towards their target.

(tense music) ♪ At a quarter past midnight, Guy Gibson and his crew arrive over the vast Möhne Reservoir.

♪ Flying alongside are Mick Martin and Hoppy Hopgood, who's now down to just three engines.

♪ Then Gibson catches sight of the dam.

It looks squat, heavy, and unconquerable, grey and solid in the moonlight.

♪ Six more aircraft are due to join them.

But Gibson doesn't know that one of them has just been destroyed.

♪ It has crashed into powerlines.

A third crew of seven are all killed.

The death toll has now reached 21, and only 14 of the original 19 aircraft remain.

(airplane rattling) (soft, tense music) ♪ The bombers' arrival at the Möhne doesn't go unnoticed.

(gunfire) Multiple anti-aircraft guns open fire as they circle the dam.

(gunfire) After surveying the landscape, Gibson breaks radio silence and calls to the other aircraft, "Well, boys, I suppose we'd better start the ball rolling.

♪ I'm going in to attack."

♪ You have to empathize with this very young man at that moment, when all the others are circling, watching.

And he's got to, from beginning to end, show them how to do it.

♪ (Mike) Before they could actually start the bombing run along the reservoir towards the dams, they had to get the bomb spinning.

When the bomb was spinning at 500 RPM, you could really feel it.

And there were stories of being bounced around just like being in turbulence.

(airplane rattling) (Dan) Gibson dives down towards the reservoir to make his attack.

(soft music) As they drop down over the water, Gibson's navigator turns on the two-light system.

Then he peers out this special window here, looking at the surface of the reservoir.

He guides him ever further down.

"Down, down, down," he says.

Then when the perfect figure-of-eight shows on the surface of the water at 60 feet exactly, he says, "Steady, steady."

(intense music) Manning a gun on the dam is SS Flak gunner Karl Schutte, the 23-year-old son of a local farmer.

He's received warning of the raid, so along with the other gunners, he's waiting.

♪ Schutte hears Gibson's bomber approaching, roaring towards him like a beast, so low he's convinced it'll crash into the dam.

(airplane engine humming) Finally, he sees the Lancaster and opens fire.

(gunfire) ♪ Gibson sees the shells hurtling past his windows.

His front gunner opens up, returning fire.

(gunfire) Then from under his feet, Gibson hears the voice of his bomb-aimer.

He's got his crude sight lined up on the dams.

He shouts, "Left a bit.

Steady.

It's coming up."

(gunfire, airplane engine roaring) Then finally, "Bomb's gone."

(bomb whizzing) (bomb strikes water) The bomb bounces perfectly, then skips over the moonlit reservoir, but doesn't quite make it to the dam wall.

(soft, tense music) As Gibson's aircraft skims the top of the dam and climbs away, the bomb sinks, then explodes.

(explosion, splash) ♪ A massive column of water shoots up, rising a thousand feet into the air.

♪ On the dam wall, Karl Schutte feels the dam shake beneath him like an earthquake.

Then a huge wave of water sweeps over the wall.

(water rushing) But the dam still stands.

A coded message of the failure is sent back to the Bomber Command operations room, where Barnes Wallis, already in a high state of anxiety, mutters in despair, "No.

It's no good."

♪ (Dr. Nubia) Barnes Wallis thought that one bomb would do it, that that would be sufficient to breach the dam.

That must've been a very low moment for everybody concerned.

Perhaps the whole mission was a waste of time, and perhaps the lives had been shed in vain.

♪ (Dan) Gibson now sends Hopgood in to attack.

He has no idea his friend is injured and his aircraft badly damaged.

(airplane rattling) "It's a piece of cake," Gibson tells him over the radio.

♪ Hopgood was a very brave, very dedicated young man whom Gibson regarded as the best pilot on the squadron.

♪ (David) The bravery of 617 as a whole is immense.

But Hopgood stands out above the rest of them.

By the time he'd reached the dams, he was down to three engines.

And he still went into his run, to attack.

(airplane engine humming) (Dan) Hopgood now thunders towards the dam.

(gunfire) The German gunners have learnt from the first attack, and their fire is much more accurate.

(gunfire) Hopgood's aircraft is peppered with bullets.

(gunfire) Stunned for a moment, his bomb-aimer releases his bomb a fraction too late.

♪ (bomb strikes water) It bounces once, flies over the dam... (splash, explosion) ...and explodes beneath.

(airplane engine roaring) ♪ Hopgood's rear gunner, Burcher, hears on the intercom, "Bomb's gone."

But there wasn't too much time to celebrate, because he sees out of his window sheets of flame coming past.

And he hears the engineer shout, "We're on fire."

With great difficulty, extracts himself from his tiny turret.

There isn't room in there for his parachute, so he grabs his parachute on the way by, crawls down here, and then decides to plug into the intercom here.

He says, "How's it going up front?"

Hopgood shouts, "Get out, you bloody fool!"

♪ Hopgood tries to climb high enough so the crew can bail out, but his aircraft is too badly damaged.

(airplane engine sputtering) ♪ Burcher opened this hatch.

And then he sees the wireless operator crawling towards him, badly injured, his legs nearly severed.

So, he picks him up and throws him out of the aircraft, just pulling his parachute's ripcord as he does so.

Then he looks down.

He sees the treetops below.

There isn't enough height, so he pulls his own ripcord inside the plane and throws his parachute out as a bundle and hops out after it.

♪ Burcher breaks his back but miraculously survives.

♪ The 21-year-old bomb-aimer, Fraser, also manages to bail out successfully.

♪ The rest of the crew don't make it.

Hoppy Hopgood stays at the controls until M for Mother crashes into the trees.

♪ (soft, energetic music) (Sir Hastings) And then it's Mickey Martin's turn, this wild Australian.

Wild on the ground, brilliant pilot in the air, the low flying specialist.

And Martin's bomb bounces just offline, explodes.

Nothing happens.

(explosion) ♪ So, you've there had-- the three best pilots in 617 Squadron have dropped their upkeeps, and they've all failed.

(muffled gunfire) (Dan) Then Gibson orders Dinghy Young to attack and courageously flies alongside him to draw away the flak.

(gunfire) ♪ Young drops his bomb perfectly, but again, the dam still holds.

♪ (solemn music) As Dinghy Young's fourth attack again fails to destroy the Möhne Dam, 10 miles away, American Joe McCarthy is attempting to attack the Sorpe Dam.

♪ McCarthy and his crew don't know that they're the only bomber left of the five assigned to attack the Sorpe.

And it's the hardest dam of all to breach, because it's an earthen dam.

A massive bank of soil with a concrete core, making it more robust even than the Möhne.

(Sir Hastings) They made their first run along the dam, and it's a shambles.

First of all, they nearly fly into the wood on the other side.

And secondly, they're far too high, and it's a mess.

So they go around, and they do it again.

And it's still a mess, and they go around again.

And here you are.

You're in the middle of Germany.

You've got everybody in the local village on the telephone, asking, "Where are the night fighters?

Where are the Luftwaffe?"

(tense music) Finally, it's only after 10 runs that the bomb-aimer at last presses the toggle and releases the bomb, which landed almost perfectly along the dam wall.

It explodes perfectly, but the Sorpe is a huge earth dam, and it doesn't break the dam.

♪ (Dan) 617 Squadron has now been attacking the dams for 20 minutes.

They've managed to drop five upkeep bombs, but the price has been terribly high.

And the dams still stand.

♪ (dramatic music) ♪ Guy Gibson and his crew, along with six other Lancaster bombers, have now been attacking the Möhne Dam for half an hour.

(airplane engines humming, gunfire) They've dropped four bouncing bombs on the dam.

(explosion) But it's still standing.

♪ (Sir Hastings) What those young men must've felt.

They'd given it their absolute best shot.

(gunfire) They'd done it so, so nearly right.

And yet, so, so nearly right wasn't enough.

(airplane engine humming) (Dan) Guy Gibson now calls J for Johnny to make their attack.

The pilot is 23-year-old David Maltby.

♪ As Maltby makes his approach, Gibson and Mick Martin circle the dam, firing on the enemy guns.

(gunfire, airplane engine roaring) On the dam, flak gunner Karl Schutte can't fire back.

His gun has seized, and the one in the other tower has been destroyed in an earlier attack.

(soldier) Achtung!

(Dan) Only one small machine gun is still firing.

(shouting in German, gunfire) (airplane engine humming) Schutte stands on the dam and waits for the end.

As Maltby's aircraft roars down over the reservoir, he feels it's almost so close he can reach out and touch it.

He can even make out the outline of the pilot's head.

(dramatic music) As Maltby approaches the dam, he can see its top is already crumbling.

Young's previous bomb had, in fact, caused a small breach.

(gunfire) Maltby releases his bomb.

It bounces four times.

(bomb striking water) Overhead, the other crews watch anxiously as the bomb strikes the dam dead center, sinks... (airplane engine roaring) (explosion) ...and explodes.

(soft music) On the dam, Schutte feels the ground shake again.

Another massive column of water goes up into the air.

Waves come cascading over the parapet and soak him.

(explosion) But this time, the water doesn't stop flowing.

(airplane engine humming) The spray from the blast obscures Gibson's view of the dam.

He's about to order yet another attack when someone shouts over the radio, "I think she's gone!"

(bright, dramatic music) ♪ Gibson flies closer and sees the entire center of the dam, 100 meters long, has collapsed.

Millions of gallons of water are sweeping down the valley.

♪ The Möhne Dam has been breached.

Once Gibson's crew have stopped screaming in celebration, he reports the success back to headquarters.

♪ (Sir Hastings) Very seldom in the Second World War was there a moment at which the mood changed so quickly in a command headquarters.

From the depths of despair to the summits of exaltation.

Bomber Harris, the skeptic, of course embraces success, and he goes straight to Wallis.

And he said, "Wallis, when you first came to me with this idea, that I didn't believe in it for a moment.

But now, you could sell me a pink elephant."

(tense music) (Dan) But the mission's far from over.

The three aircraft that haven't yet used their bombs now fly 50 miles from the Möhne to their next target: the Eder Dam.

(airplane engines humming) Gibson and his second-in-command, Dinghy Young, go with them to direct the attack.

♪ In 1943, the Eder is the biggest dam in Europe, the pride of Germany.

It's a symbol of their engineering prowess and power.

119 feet thick at its base and 138 feet high, its 17-mile-long reservoir contains one and half times more water even than the Möhne.

Its destruction will strike a devastating blow to German morale.

♪ Fog has built up in the valleys.

Gibson is struggling to find the massive dam.

He flies along the reservoir for five minutes before he eventually spots it.

♪ Fortunately, there are no defending anti-aircraft guns.

But that's because the area is so hilly, the Nazis think it's impossible for any bomber to make an attack.

♪ You had this very narrow approach to the dam.

And then just past the dam, you've got this almost wall of rock.

So you've got to make the steep approach.

You've got to hit your height right.

And then the moment you've dropped the bomb, you've got to climb flat out.

Or you were going to go straight into the wall of rock.

(soft, tense music) (Dan) L for Leather is the first aircraft to attack.

Unable to get down to 60 feet in time because of the hills, they make multiple failed attempts.

♪ Finally, they drop their bomb.

It hits the center of the dam perfectly... (splash) (explosion) (airplane engine roaring) ...and explodes.

♪ But the dam holds.

♪ And there are now only two bombs remaining at the Eder.

(airplane engine humming) Next, Gibson orders 21-year-old Old Etonian Henry Maudslay to attack.

Henry Maudslay's bomb drops too late.

There may have been something wrong with the trigger mechanism.

As a result, it bounces once.

Then it smashes into the parapet of the dam.

The weight of that impact means that it explodes immediately.

(explosion) ...and that explosion then catches Maudslay's plane as it shoots low over the dam itself.

Gibson radios, "Henry, Henry, are you okay?"

He receives a faint reply: "I think so.

Stand by."

♪ Then nothing more.

(airplane rattling) Henry Maudslay and his crew aren't okay.

40 minutes later, their damaged, burning aircraft proves easy prey for German gunners near the Dutch border.

(gunfire) (somber music) No one survives.

♪ (soft music) (airplane engine humming) ♪ There's now only one aircraft left at the Eder with a bomb.

♪ It's their last chance to break the dam.

N for Nuts, flown by 22-year-old Australian Les Knight.

A deeply religious Methodist, this quiet, meticulous man is a non-drinker who avoids the beer-fueled social life of the squadron.

(gunfire) (airplane engine roaring) Despite the immense pressure, Knight and his crew drop the bomb perfectly.

(bomb striking water) And it strikes the Eder Dam dead center.

(explosion) As Knight climbs steeply to avoid the high ground in front of him, the bomb explodes.

Gibson, who's flying just above Knight, looks back and sees the base of the dam has been blown away.

It looks like, he says, a gigantic hand has punched through cardboard.

(soft music) A 30-foot-high tidal wave thunders down the valley, sweeping away the cars, buildings, bridges, and people below.

(somber music) (Victoria) The deluge coming from the breached dams is absolutely colossal.

This sort of roaring power that's pushing everything in its path downriver.

♪ (Sir Hastings) In fact, there's something like 1300, 1400 people who died.

A large proportion of them women slave laborers who were no friends of Hitler, who were friends of the Grand Alliance and Hitler's slaves.

It was a huge human catastrophe alongside a great triumph of British technology and British courage.

♪ (Dan) As floods cascade down the valleys... (airplane engine humming) ...the five aircraft of the reserve wave are still making their way low-level towards Germany.

(grim music) (Sir Hastings) The reserve wave didn't achieve much, and they also suffered very heavily.

(airplane engine humming) One got lost and turned back without dropping his bomb.

One did drop his bomb, and to this day, nobody's quite sure which dam he dropped his bomb on.

(Dan) Tragically, two of the reserve aircraft are shot down on their way to the Sorpe.

(gunfire) (explosion) (Sir Hastings) Brown in F for Freddy did make an incredibly brave attempt to break the Sorpe following Joe McCarthy.

But again, it failed to break the dam.

♪ (birds chirping) ♪ The 12 surviving crews now have to get home.

As dawn approaches, the skies lighten, and they lose their protective cover of darkness.

They can be seen by the German fighters.

On top of that, they've lost the element of surprise.

The Germans know only too well where they are.

♪ (tense music) ♪ The 12 surviving dambuster crews are racing home at extreme low level across Nazi-occupied Europe.

♪ The five aircraft that attacked the Eder Dam have reached Holland.

♪ Dinghy Young is approaching the Dutch coast.

He and Gibson are the pilots who've spent most time over enemy territory.

♪ (airplane engine roaring) As Dinghy crosses the coastline, he knows they're now as good as home.

♪ (solemn music) ♪ The other pilots think that Dinghy Young flies too high.

Yes, it's easier to navigate and avoid hitting things on the ground, but it makes you very visible.

And sure enough, as Dinghy Young takes his aircraft roaring out over the coast of Holland towards the North Sea, he's hit by anti-aircraft fire from the ground.

This time, there's no miraculous sea rescue for Dinghy Young.

He and his crew are killed instantly when their Lancaster crashes into the sea.

♪ (tense music) ♪ At RAF Scampton, the ground crews have been waiting up all night for the attackers' return.

♪ First home is Mick Martin in P for Popsie.

The third pilot to attack the Möhne, he's been at the controls now for five hours and 40 minutes.

♪ 23-year-old Maltby, whose bomb broke the Möhne, lands immediately afterwards.

(cheering, applause) They're elated.

(cheering, applause) ♪ Someone asks Maltby how it went.

"Marvelous, absolutely marvelous", he enthuses.

"Water, water everywhere.

I've never seen anything like it in my life."

But then his tone changes.

"Hoppy's bought it," he says, "shot down over the target.

Some of them never even got there."

(airplane engine roaring) As dawn brightens over Scampton, more survivors limp home.

Almost every aircraft has damage.

After six and a half hours in the air, Gibson lands at 4:15 a.m. (airplane engine roaring) At 6:15 a.m., the final plane arrives home, flown by Townsend.

♪ By this time, Barnes Wallis and Bomber Harris have arrived at Scampton from headquarters.

(airplane engine humming) As the exhausted Townsend clambers out of his aircraft, there's a large crowd waiting to hear how it's gone.

One senior officer in particular steps forward, asking what happened.

He just pushes past him, saying, "Wait until the debrief."

Only later does he realize that man was Bomber Harris.

(serene music) ♪ Guy Gibson and the other survivors have already headed here to the officers' mess, where a party is underway in the bar.

♪ Later in the morning, the party moves on here to the station commander's house, where Barnes Wallis is staying.

♪ Wallis is seen emerging from his room in a dressing gown with tears in his eyes.

(airplane engine humming, muffled gunfire) He's devastated by the loss of life that has resulted from his project.

(soft music) Gibson tries to comfort him, unsuccessfully.

♪ Of the 133 men who went on the raid, only 80 survived, and three of them were prisoners in German hands.

It was a shockingly high price to pay.

Following their early morning party, the surviving pilots gather here in front of the officers' mess for a group photo.

♪ On the end stands Anderson, the reserve pilot who'd got lost and turned back without dropping his bomb.

♪ To Gibson, it's unacceptable.

Soon after this photo is taken, Gibson throws Anderson out of 617 Squadron and sends him from Scampton in disgrace.

♪ (tense music) Over in Germany, Albert Speer, Hitler's armaments minister, is woken and told of the raid.

♪ He flies over the broken dams, then lands to inspect the damage.

♪ (Sir Hastings) Albert Speer sees these great sheets of water extending over farmland and villages and towns.

Speer was absolutely devastated.

♪ The shock to the Nazi leadership is hard to overstate.

♪ (Victoria) The dams raid struck so much fear into the heart of the Nazi leadership, because they had never anticipated a challenge and a blow to that kind of scale.

And Joseph Goebbels, who was Hitler's spin doctor, had once commented that the English have never invented anything original.

But this time, they had.

(soft music) (Dan) As the exhausted crews finally head to bed, news of the attack breaks.

It marks a turning point in the war for Britain, supplying a much-needed morale boost for people who've been fighting for four years.

♪ Although the results of the deluge in the short term were undeniably impressive for the British, it didn't really have the lasting impact and the knockout blow that Wallis was anticipating.

So, everything was repaired relatively quickly.

♪ (Sir Hastings) By the time the autumn rains came, the Möhne Dam and the Möhne Reservoir were back in business serving rural industry.

The biggest mistake made by the British-- if they'd bombed the dam repairs, then they could have transformed the attack on the Möhne and the Eder from just an inconvenience and a shock to Germany into a really serious blow to rural industry.

But they failed to do this.

♪ (Dan) The aircrew who survived the raid are given a week's leave, but soon, they're flying again.

(somber music) (airplane engine humming) ♪ Of the 77 young men that returned from the dambusters raid that morning, 32 of them would be killed in action before the end of the Second World War.

♪ David Maltby, whose bomb breached the Möhne Dam, died along with his entire crew four months after the dambusters raid.

♪ Most of Gibson's crew died the day after Maltby.

But Gibson himself was on a publicity tour of the USA by then.

♪ Anderson, the disgraced pilot, and his entire crew were killed eight days later.

♪ Barnes Wallis never got over the loss of life brought about by his idea.

♪ He'd forever refuse to answer when asked how he felt about the men who died that night.

♪ Guy Gibson was taken off frontline duties.

But on the 19th of September, 1944, he chose to lead a raid over Germany.

And coming back, flying low level over Holland, he crashed and was killed.

♪ Only 48 of the 133 dambusters would survive the Second World War.

♪ (soft music) ♪