All language subtitles for World War II Secrets from Above - S01E04 (2022) WEB.eng

July, 1942.

In a remote corner of Wales, the Allies
test a pioneering top-secret bomb.

They're planning to blow up German dams

to paralyze Hitler's booming war machine.

To attempt this perilous raid,

the Allies assemble
state-of-the-art aircraft

and a crew of top gun airmen.

But they'll also need courage, ingenuity,
and a large dose of luck...

to pull off one of the most
audacious bombing missions in history.

In this series,

we investigate the most
extraordinary events of World War II

from a brand-new perspective.

Matching rarely seen archive film,

photography from the front line,

and remarkable
aerial reconnaissance images

to their original locations.

We reconstruct the crucial battles,

daring bombing raids,

and deadly terror weapons

that changed the course of history.

Soaring over the battlefields,

we reveal the secrets of World War II

from above.

June 1940, the Ruhr Valley, Germany.

These are the heartlands
of Hitler's booming war industry.

This vast expanse of water
is being held in place

by one of the critical piece
of Nazi infrastructure,

the Möhne Dam.

Built in 1913, the colossal structure
stands 40 meters tall

and stretches 300 meters
across the valley.

Nearby factories and mills
rely on this water

both as a raw material
and to generate hydroelectric power.

The Möhne Dam epitomizes

the strength and scale
of German engineering and industry

that's underpinning and fueling
the Nazis' expansion across Europe.

In the west, they've driven the
British and French armies into retreat,

with hundreds of thousands fleeing
from Dunkirk to England.

Through June of 1940,

the Nazis continue to steamroller
to the west and south,

occupying large parts of France.

The Allies can't compete
on the battlefield.

Instead, the commanders decide
to attack the industries back in Germany

that are supporting and fueling
Hitler's armies,

many of which are concentrated
along the Ruhr Valley.

One of the most important
industrial complexes in the Ruhr Valley

is the Zollverein coal mine.

Zollverein's 55-meter tall winding tower
is known as the Eiffel Tower of the Ruhr.

It is the biggest colliery in Europe.

The coal produced here
is a key ingredient in steel production,

so the Nazis need it in vast quantities

to build guns, tanks, and submarines.

Resident specialist Hanna Lohmann

explores this critical piece
of infrastructure.

So Germany at the time

needed the power and needed the steel
and needed the coal.

We are talking about the black gold.

Almost sounds like a marketing thing
to say black gold,

but it definitely was.

The miners were very crucial
to keep the war going.

Seven thousand people work here,
but life as a miner is tough.

Back in those days,
in the 1940s,

it was actually hard labor by hand.

This, for example, this drill,
like, I can hardly lift it,

I can hold it for a few seconds.

But if you imagine that this
was not vibrating but literally shaking,

and you would be doing this
for many hours,

then you have an idea of
how hard the work was in the coal mine.

People would be working here
in three shifts to keep the place running.

The machines
were not supposed to stand still.

In 1940,

Zollverein produces
over 3.5 million tons of coal every year.

Mines like this are the heart
of the Nazi war machine.

They would call this place
the Land of the Thousand Fires,

because when you come here
in the nighttime,

the sky would be very light,
full of orange and red from the heat

when they were working
in the steel factories.

If the Allies are going
to defeat Hitler,

they need to find a way
to paralyze this booming production line.

Fortunately, the commanders think

they've spotted
the Ruhr Valley's Achilles' heel.

In addition to Zollverein,

there are numerous other coal mines

and dozens of steel mills
across the region.

The smooth running
of all this industry relies on two things,

water and power.

Both of these come
from the sprawling local river network,

with huge dams in the hills to the east.

The Allies set out on a mission
to blow up three of these dams,

the Möhne, the Sorpe, and the Eder.

Historian Victoria Taylor

investigates why the Möhne Dam
is the prime target for the Allies.

If you actually want to paralyze
a nation's war effort,

you really need to be going
for the heart of its industry.

And this is what the Ruhr Valley was,
and indeed, what the Möhne Dam was.

You can go straight to interfering
immediately with steel production

that makes tanks and planes
and other war equipment.

Then the Germans
are truly stopped in their tracks.

When you see
strong imposing structures like this,

you can start to tell why the Ruhr Valley

was known
as the "Waffenspiele des Reiches"

or the Armory of the Reich.

In the war, this dam

really was a point of immense pride
for the local community.

The dam's about
three to four meters across.

By standing here, you really start to
get a sense of just how solid this dam is.

You can see here my hand for comparison

against just one block
within this masonry dam.

The limestone masonry
extends 40 meters down

to the bottom of the reservoir.

A clay bank on the waterside
protects against leaks,

and the wall widens
to 34 meters at its base.

Its foundations are locked
into three meters of bedrock.

Combined, this gives the dam
colossal strength,

enough to resist the pressure
from over 100 million tons of water.

Blowing a hole in this mighty wall
will be a formidable technical feat.

But one person is up for the challenge,

Barnes Wallis.

If there's any aeronautical
engineer that is qualified

to try and make a crack
at a dam like this, it's Wallis.

But the problem is
this has never been done before.

He's got to try and create a bomb
that's light enough to be transported,

but heavy enough
to smash this sort of dam into pieces.

Wallis quickly realizes

the only way to produce
enough destructive energy

is to create a huge explosion
deep underwater, behind the wall.

The question is,
how much charge is required

and how close does it need to be?

This is not a sum
that can just be done on paper.

Wallis heads
to a scientific research center

30 kilometers northwest of London.

This secluded woodland
looks inconspicuous from above.

A small stream snakes its way
through the trees.

But beneath this canopy,

Barnes Wallis's team
starts their top-secret experiments

in November, 1940.

Over seven weeks,

they intricately construct an exact
miniature replica of the Möhne Dam.

They use around two million tiny blocks

to produce this one-fiftieth scale model.

Every detail must be perfect
for any results to be valid.

Engineer Zainab Adigun
explores Wallis's outdoor laboratory.

This is so cool. It's really tiny.

In order to start
to test out your theories

and test out the constraints
and understand what they are

and how much impact they have
on your design,

you have to start small.

By starting off small,
you're able to easily identify

what the issues may be.

Wallis must first calculate

how close the explosive charge
needs to be to the wall

to bust the dam.

Water, essentially, is quite dense,
so it actually acts as a buffer.

So, if you're passing charges
through water,

it would dissipate quite quickly.

So, in order to feel the full effect,
you want to be as close as possible.

It will take a lot of precision.

The scientists position
a test probe

up against the dam wall

to measure the deflection.

They use a wooden pole to drop the charge
to the bottom of the water,

90 centimeters from the dam.

No damage.

They continue the tests,

reducing the distance
between the wall and charge.

Eventually,

the dam is breached.

For Wallis and the scientists,
the evidence is clear.

To have any hope of success,

the bomb needs to explode
as close to the wall as possible,

and it'll almost certainly
take more than one direct hit.

By being as close
as possible to the wall,

he could use less of explosive,

so it's not too heavy,

but he's still getting the impact
that he needed to blow up the dam wall.

Wallis and his team now need
to confirm these small-scale results

can be recreated
on a dam ten times larger.

They head to Wales.

An isolated corner in the Elan Valley

provides the perfect location
to scale up their experiments.

A local water authority

has given the scientists permission
to use Nant-Y-Gro dam.

It's constructed of concrete and masonry,
just like the Möhne in Germany.

It's also exactly one-fifth of the size.

In July, 1942, the scientists prepare
their super-sized apparatus.

Like in the small-scale trials,

they use a pole to set the charge
slightly back from the dam wall,

before lowering it down into the water.

With 127 kilograms of high explosives
at a depth of three meters,

Barnes Wallis climbs a nearby bank
to watch from a safe distance.

Success.

The bomb blows a hole 18 meters wide
and seven-and-a-half meters deep.

The challenge now facing the Allies

is how to get the explosives
into this exact sweet spot

on the mighty German dams.

From high above
the Möhne reservoir in the Ruhr Valley,

Allied reconnaissance photos
reveal two long booms

on the waterside of the dam wall.

The booms support a pair of nets

which extend
to the bottom of the reservoir.

The nets are designed to protect
against an underwater torpedo attack,

and it would be virtually impossible
to land a conventional bomb behind them.

The Allies must think outside the box.

Inspired by skimming stones across water,

Barnes Wallis devises an ingenious plan.

He sets about inventing
a brand-new type of missile,

one that can bounce across water.

Wallis proposes launching the bomb
from a low-flying plane

and making it jump over the nets.

But for it to bounce, it needs to spin.

If the bouncing bomb is spinning forwards,

it'll accelerate
each time it hits the water

and is likely to jump over the dam wall.

Instead, Wallis's team suggests
spinning the bomb backwards.

As it skims across the water,
the backspin will slow it down,

and when it hits the dam,

it should make the bomb
cling to the wall as it descends.

A pressure-controlled detonator
will then trigger at the optimal depth.

It's a highly ambitious plan.

Wallis must carefully calculate
the speed and height needed

for the plane carrying the bomb.

He also needs to determine
exactly when the bomb should be released

and how fast it should be spinning.

To formulate a plan of attack,
the team heads to the beach.

In December, 1942,

Wallis and his team of scientists arrive
at Chesil Beach in Southwest England.

This secluded 12-kilometer lagoon
that runs alongside the beach

provides an ideal arena
for their top-secret tests.

Wallis persuades the air ministry

to convert a Wellington bomber
to drop one of his early prototypes.

The spherical test bomb
is hung beneath the aircraft

so it can be spun before it's released.

On the 4th of December,

Barnes Wallis himself is on board
as the plane approaches the lagoon.

Engineer Zainab Adigun

understands the challenges
facing the creator of the bouncing bomb.

This was the first time
they've actually started

to drop the bombs out of the planes.

getting the theory out
into the practical world.

The scientists film the trials
in slow motion

to calculate exactly how
the bomb should be dropped.

There are so many
different variables,

and so there's a lot of places
where error can happen.

But in reality, you have an ideal spot
where you want the bomb to stop.

It all comes down to precision.
There is no room for error there.

The shallow lagoon

means the prototype bombs
can easily be recovered

for inspection and analysis.

Gosh, it is literally
like a massive golf ball.

Dimples must have been part of his design.

So that must have helped in terms of
the aerodynamic property of the bomb

as it travels through the air
and through the water.

You know how you can
backswing a golf ball,

that's how you control the trajectory?

So he used the basis of that,

and then employed that in his design,
which is genius.

A golf ball and a bomb,
it's completely different,

but when you think about it,
the physics behind the two, very similar.

The trials continue.

But while the bomb successfully bounces,

Wallis and the team struggle to control
its spin and direction.

In Lincolnshire,

the RAF has selected
one of their newest trail-blazing aircraft

to drop Barnes Wallis's bouncing bomb.

This is the Avro Lancaster.

The plane is 21 meters long...

and has a wingspan of 31 meters.

With four Rolls-Royce Merlin engines,

it can fly more than 4,000 kilometers
without refueling.

So the German dams
are easily within range.

Pilot and former marine Arthur Williams

explores this ground-breaking
heavy bomber.

The Avro Lancaster formed
the backbone of Bomber Command

during the Second World War.

We needed an aircraft
that could fly long-range,

penetrate deep into enemy territory,
and carry a large payload.

We also needed an aircraft
that was reliable.

Four engines gave the crews
that reliability.

And you see
the first of the Merlin engines.

She's really visually notable
because of the massive chin radiator

that sits on the underside,
powering this massive propeller along.

Up there, you've got the cockpit,

and you've got
the bomb aimer's position underneath.

This piece of Perspex here,
the flat bit at a slight 45 degree angle,

gives an uninterrupted view
of the target beneath,

so he'd be able to see
exactly at what point to drop his bombs.

One of the distinguishing features
of the Lancaster

is its twin tail configuration.

And then we come to the business end
of the bomber, the rear turret.

The reason there's four machine guns here

is because the bomber
is most vulnerable from the back.

If a German fighter
is gonna attack the aeroplane,

they'll generally come from the rear,

which is why,
unfortunately for the rear gunners,

they were the most vulnerable.

They were often, on many raids,
the first people to get killed.

In addition to the four guns
on the rear turret,

there are two machine guns
on the top of the aircraft,

and a further two on the front.

These aircraft gun turrets

have an ability to turn, rotate,
and point up and down,

so they give the Lancaster
a pretty decent arc of defense.

They'll certainly
make a German fighter pilot think twice

about how long he wants to
stay on the tail of a bomber for.

Coming under the aircraft, you can't help
but notice this vast space here.

This was to contain all of the aircraft's
14,000 pounds worth of bombs.

But of course, for the Dambusters Raid,

this was all stripped out
and replaced with one bouncing bomb.

There is no doubt
this plane is capable

of launching Wallis's bouncing bombs
towards the German dams.

But to stand any hope of success
on such an audacious mission,

they'll need a top gun crew to fly it.

The commanders assemble a crack team
from across the Allied air forces.

They form a brand-new RAF unit
named 617 Squadron.

The planners
of this mission knew that

for the average Bomber Command pilot
it would be virtually impossible,

so they had to have the very best crews

in order for this operation
to stand a chance of succeeding.

They needed pilots with the experience

of flying multiple operations
over Germany,

who wouldn't be shaken by the prospect
of facing enemy flak.

The planners choose
an enigmatic 24-year-old called Guy Gibson

to be the squadron leader.

Guy Gibson was selected because
he was an extremely competent pilot

and he'd flown a wide variety of aircraft,
both twin-engine and multi-engine bombers,

on various different types of raids,

which is why Bomber Command selected him,
because of his broad range of experience,

and he was
a very good leader of men as well.

Even with the crème de la crème
of the Allied airmen

and this new state-of-the-art aircraft,

the operation will test the crews
to their limits.

The Germans know
that their dams could be a target,

so they fortify the Möhne Dam.

They've positioned an anti-aircraft gun
at the north end of the wall,

and one on each tower.

Combined, they can launch

more than 2,000 20mm shells
into the sky every minute.

As well as the manmade defenses,

617 Squadron will have to avoid
hilltops and other obstacles

as they descend to drop their bombs.

Victoria Taylor investigates
the valley's natural defenses.

The challenges associated with
bombing this dam are absolutely immense.

You can already see
that there's an army of trees

that are going to be densely populated

in the springtime of 1943.

And we've also got to bear in mind
that this is an industrial region as well,

so you've got this haze
that's coming over above

from all the different
factories and installations.

And, of course,
that is obscuring visibility as well.

But even to get here,
the journey is incredibly perilous.

They're needing to contend with guns,

trying to avoid
being detected on German radar.

They need to make sure they're not getting
picked off by German night fighters.

And so, really,
when you add that plus this challenge,

this really should be impossible.

617 Squadron
will first come into range

of the Nazis' coastal early warning radar.

As soon as these stations
detect enemy aircraft,

Luftwaffe fighter planes
can launch within minutes

from aerodromes positioned along the line.

The Nazis have built

a second densely packed line
of radar stations and aerodromes

just to the west of the three target dams.

To give 617 Squadron any hope

of not being spotted
by this web of defenses,

they must cross the channel at night.

They'll also fly below 30 meters altitude,

which should stop them being detected
by the German radar.

But the darkness conceals other hazards.

Sand dunes that can soar
over 50 meters high

line the northern coastline
of mainland Europe

and will be hard to spot at night.

The Lancaster pilots
must also dodge power lines

and even tall trees.

We can't overemphasize
just how dangerous low-level flying was.

We gotta remember the Lancaster
wasn't designed as a low-level aeroplane,

it was designed as a high-altitude
or a medium-altitude bomber.

This is proper chain-operated
analogue flying.

When you turn that control column,

there is a piece of wire and chain
that goes out to the wing

that pulls the aircraft
over to the left and right.

It's a bit like an old London bus, really.

It's not just the pilots
who will struggle

flying at night and at such low altitudes.

It'll take exceptional skill
from the navigators

to stay on course
for their three-hour flight.

They'll use a specially designed dome
in the center of the plane

to take readings in the night sky.

Many of the navigators
on these bombing raids

would be used to flying at high altitude,

where they've got a bit of time

to take a look at where the moon
and the stars are aligned

in order to give them
a celestial position,

but also taking reference from
what we can see on the ground.

Navigating from high altitude
is considerably easier

than when you're doing it at low level.

Because you're flying so fast,
the ground is rushing past you so quickly,

it's almost impossible to see
from any terrain where you are.

You could see a railway line,
you could see a road,

you could see a series of buildings,

but that could be anywhere
in occupied Europe.

So just knowing where you are
and finding your way to the target

would've been incredibly difficult.

Despite the awesome scale
of the bomber on the outside,

inside it's anything but spacious.

This is where the crew
would've entered the aeroplane.

You can see all of the positions.

We've got the top turret there.

Navigator's position, radio operator.

Pilot's cockpit's right up there.

And then down here,
this lonely, gloomy-looking space

is where the rear gunner would've sat.

it is quite a claustrophobic space,

but when you think the seven-man crew
with all of their cold-weather gear,

all of their oxygen
and everything strapped on,

it's gonna be even more
claustrophobic and cramped.

In these cramped spaces,

the men of 617 Squadron
are in the air for five hours a day,

flying training missions
through the spring of 1943.

During the raid on the dams,

their ability to maneuver
this monstrous aircraft at low altitudes

could be the difference
between life and death.

While the airmen hone their flying skills,

the development of the bouncing bomb
has moved here,

to Reculver Bay
on the north coast of Kent.

Barnes Wallis remains convinced
a spherical shape is essential

to keep the bomb's trajectory true.

But this time,
the real-world tests prove him wrong.

The prototype bomb
remains hard to control.

And breaks up on impact with the water.

Wallis decides to try a cylinder instead.

On the 11th of May, 1943,

the first crews from 617 Squadron fly in

to begin their trial runs
with his revolutionary weapon.

Engineers have adapted
the undercarriage of the Lancasters

and suspended Wallis' latest prototype
beneath the aircraft.

In the early tests, some bombs overshoot,

while other stop short.

But after weeks of tests,
the team finally cracks the formula.

The Lancaster must be flying
at just 20 meters,

travelling at 370 kilometers an hour,

with the bomb rotating backwards
at exactly 500 revolutions per minute,

and be released between 365

and 411 meters from the dam wall.

Achieving every one
of these precise individual parameters

seems nigh on impossible.

Despite this, in just three days,

617 Squadron will fly 19 Lancasters
deep into Nazi Germany

in the hope that at least one
can pull off the impossible.

This will be one of the most audacious
and high-risk bombing raids in history.

The task at hand
was an incredibly difficult one.

And the RAF, the pilots,
and the crews know this,

but there's no other way around.

They've got to
punch their way into Germany

and do the job they need to do.

Late in the evening
on the 16th of May, 1943,

the Lancasters of 617 Squadron
depart from Lincolnshire,

each armed with a single bouncing bomb.

One of the bomb aimers on board
is Johnny Johnson.

We flew low,
out into the moonlit North Sea,

and we headed for the Dutch coast.

We were aware that the gunners there
would recognize the noise,

they'd be ready for us.

Anyone who wasn't a bit apprehensive

was either devoid of emotion
or a stranger to the truth.

The planes take
two different routes,

to try and confuse the German defenses.

Five Lancasters
take the longer, northerly route,

while the 14 others fly further south.

As they approach the Dutch coast,

one plane is shot down

and two others are damaged
and forced to return home.

Further inland, more Lancasters
are shot down or hit power lines,

so as they near the dams,
only 12 aircraft remain.

Shortly after midnight
on the morning of the 17th of May,

Guy Gibson arrives
over the Möhne reservoir.

He will be first
to attempt this Herculean feat.

As he lines up with the dam wall,

he must make sure his altitude
is exactly 20 meters above the water.

To achieve this level of accuracy,

the aircraft shines two narrow beams
down onto the surface of the water.

When the beams perfectly align,
they release the bomb.

Under heavy fire from the German guns,

Gibson pulls up
as Wallis's bomb sinks into the water.

It explodes short of the wall.

For the German defenders,
it's a harrowing sight.

One of the gunners is Alfred Lengert.

The second bomb drops.

This time it's released too late.

The bomb flies over the wall

and explodes in the valley below.

To make matters worse,

the Lancaster has been damaged
by the German flak and crashes nearby.

Five of the crew perish.

Undeterred, Gibson calls in the next plane

and circles round to try
and draw some of the flak fire.

As he called each aircraft
in turn, he flew alongside.

This to me says,
"You're doing this, I'm doing this,

"we're doing it together."

And that, to me,
is the essence of good leadership.

The third bomb dropped,
veered sharply off course,

and explodes without causing any damage.

But the pilot joins Gibson
in circling around

to provide cover for the fourth attempt.

After bouncing three times,

the bomb hits the wall

and sinks deep into the water.

The underwater explosion
fails to breach the mighty dam.

The raid has now been going
for over 20 minutes.

Four of the squadron's bombs
have been dropped without success

on the Möhne,

and the threat of the Luftwaffe arriving
is growing fast.

Gibson calls in the next plane.

The crew release bomb number five.

As the pilot pulls up,

the backspin makes the bomb
cling to the dam wall,

just as Wallis predicted.

The explosion sends
a plume of mud and water

300 meters into the sky.

And blasts a hole 76 meters wide
in the dam wall.

Against all the odds, 617 Squadron
has breached the mighty Möhne Dam.

The remaining Lancasters drop their bombs
on the two other targets.

The Sorpe Dam is barely damaged,

but they succeed in blowing up the Eder.

The surviving crews
begin their long journeys home.

The route out
took us straight over

what had been the Möhne Dam.

There was water everywhere.

Water was still coming out of the dam.

And this must've been 20 minutes,
perhaps half an hour, since the breach.

So we had at least the satisfaction

of seeing some real results
for the endeavors of that raid.

The flooding causes devastation
along the Ruhr Valley.

This is a major setback for Hitler
at this crucial time in the war.

Factories, mills, and mines are paralyzed
as towns are inundated,

just as the Nazis are being pushed back
by the Soviets in the east.

The Dambusters Raid
kills nearly 1,400 people.

But they are almost all civilians.

617 Squadron have also
suffered heavy losses.

Of the 133 aircrew who attacked the dams,

53 have been killed,

most in their early 20s.

Despite this, the raid is a huge victory
in the propaganda war.

King George comes to Lincolnshire
to meet the survivors in the squadron.

They're hailed as heroes,

and the Allied Commanders
spread the news far and wide

to boost morale.

The tide of the war is turning.