Nova (1974–…): Season 43, Episode 13 - Bombing Hitler's Supergun - full transcript

Historians and engineers investigate how Allied forces conspired to destroy Hitler's "supergun".

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It is the height of World War II

Allied intelligence officers
spot something terrifying:

the muzzle of an enormous cannon

protruding from an underground
Nazi bunker

It's a supergun,
a monstrous new weapon,

part of Hitler's plan
to reduce London to rubble

and win the war through terror

It's a very cruel and it's
a very nasty way of making war,

but they believed it might work

The Allies hatch two bold plans
to defeat it

One involves Joe Kennedy Junior,



eldest son of what would become
an American political dynasty

He would be piloting
an explosive drone

What happened to Joe Kennedy
and his co-pilot on that plane

is actually one of the greatest
mysteries of World War II

The other scheme

would use the biggest bomb
the world had ever seen

But would either plan work?

Three, two, one!

Now, in a series
of explosive experiments,

engineer Hugh Hunt
will investigate

the Allies' bunker-busting
technologies

It's vanished

There's ground zero,
and there's nothing there

And he will build
his own supergun



Firing!

To see if the weapon

really could have brought London
to its knees

"Bombing Hitler's Supergun,"
right now on NOVA.

By spring of 1943,
the tide of World War II

was beginning to turn
against Hitler

In an effort
to regain the offensive,

he drew up plans
for the world's biggest gun,

with 25 barrels

This enormous cannon
would be buried deep underground

in Nazi-controlled France

It was designed to fire shells
100 miles,

cripple London, and pave the way
for a Nazi victory

In a desperate race
to knock out Hitler's supergun,

the Allies devised
their own miracle weapons

The Americans
pioneered the drone,

a radio-controlled heavy bomber

packed with 12 tons
of high explosives

Leading the drone mission was
29-year-old Joe Kennedy Junior,

a man groomed from birth

to be the first Catholic
president of the United States

The British drafted in

the brilliant engineer
Barnes Wallis

He came up with the original
bunker buster,

a bomb that would
explode underground

and trigger
a man-made earthquake

The Allied efforts were focused

on the tiny hamlet
of Mimoyecques,

five miles inland
from the French coast

On the surface,
it's now just a ruin,

but hidden inside
this hollowed-out hill

is the secret installation built
to house the V-3 Nazi supergun

Good grief!

I can't quite make sense of this

This isn't natural rock,
this is concrete

No, this is a roof, look at it!

It's four or five meters thick!

Engineer Hugh Hunt

and battlefield archaeologist
Tony Pollard

have been drawn here
to find answers

to the many questions
that remain

about this mysterious
superweapon

This was the entrance
of a tunnel?

Yeah, it looks as though
there is some sort of hatchway

How did it work?

Was it powerful enough
to hit London 100 miles away?

And could it have ended the war?

These are the mysteries
that Tony and Hugh

are trying to solve

This is a glorified pillbox
with a 130-meter-long gun

I'd love to see
what's underground

Right, let's go

The fortified bunker

has not been fully explored
since the war

Whoa!

That's slippy, that's slippy

You okay?
Yeah

They rappel down
one of the steep shafts

that would have each contained
five barrels of the supergun

Wow, look how steep it looks
from the bottom!

This is certainly big

This, we reckon,
is about 50 meters

And it was 130 meters

And this is one third
of the way down

The shaft extends a further
300 feet beneath them,

but now it's blocked by rubble

Today, there is no sign
of the barrels,

but the design of the shaft
reveals a telling detail

This tunnel is centered very
accurately on a particular line

Here we are,
here at Mimoyecques,

and this particular tunnel
that we see here

points directly over here
at Westminster Bridge,

which is astonishing

Hitler's gun was trained
right on central London

By the spring of 1943,

the Nazis had tasted defeat
in the deserts of North Africa,

and they had been driven
from the Soviet Union

after a bloody battle
at Stalingrad

Hitler was determined
to strike back

Taking center stage
in his war room

was the supergun,

or the London Cannon,
as he called it

Its five shafts
would each contain five barrels

That's a total of 25 barrels

firing 300 shells an hour,
24 hours a day

Maintaining this onslaught

would require
an enormous infrastructure:

a network of galleries
to store ammunition,

1,200 troops to man the guns,

and an underground railway
to supply them

This was artillery warfare
on an industrial scale

Whoa!

Hugh and Tony explore

the farthest reaches
of the complex,

looking for clues
to how the tunnels were built

It's almost like a city
underground, isn't it?

Yeah

Look at this, Hugh, look

What they've done is they've
actually used drills or spikes

What they find shows them
the tunnels were carved by hand

using pick axes and jackhammers
with steel spikes

Look at that!

Look at that!

That fits

They're just using them
to prize away

fragments of the stone

And imagine the effort,

all day, every day,
hammering these spikes in

and then moving away
all the rubble

It's just a horrible thought

The supergun's first victims
were not the people of London,

but the slave laborers
who built the installation

This complex was built
by a large number of people

that had been conscripted
against their will

And there can be no doubt

that many, many people
lost their lives

This wasn't
a normal building site

Work here never stopped

They had gangs of workers
on site

24 hours a day, 7 days a week

The priority here was
to get those guns into action,

and the human cost didn't matter

Hitler wanted to rush
his wonder weapon into action

because he was hungry
for revenge

He had bombed London
during the blitz

in the early days of the war

But since then, his Luftwaffe
had lost air superiority

in the skies over Europe

The Allies were exploiting
this lack of air cover

by relentlessly bombing
German cities

In return, Hitler began building
fortified installations

all over northern France:

massive concrete bunkers
hidden in remote woods

that would house a new
generation of secret armaments

called V-weapons

They're called the V-weapons

because they're about vengeance

They're about retribution

This is Hitler
getting his own back

What the RAF and the American
air force have been doing

is bombing German cities,
killing German civilians

And Hitler is absolutely
outraged by this

and decides he's going
to take it out on London

So all of these weapons
are designed

to hit London from France

These were technologies
straight out of science fiction

There was the V-1,
a jet-powered flying bomb

There was the V-2,

a rocket that would shoot
beyond the stratosphere

before falling back to earth

These weapons had the potential
to reduce London to rubble,

but they were untested in battle
and unreliable

Initially at least,
Hitler was fairly skeptical

about these new
experimental weapons

Rockets and missiles,
not really his bag

His was a more traditional
military background

molded in the trenches
of the First World War

But what that experience
did give him

was knowledge of how effective
artillery could be

He'd seen how artillery
could cut men apart

Upwards of 80% of the casualties
on the Western front

were caused by artillery

And the V-3 was a supergun

It was old school,
but with a new twist

The twist was that
unlike traditional artillery,

the shells of the V-3 supergun

would not be falling
on frontline soldiers,

but raining down on London's
terrified civilians

In September 1943, in a country
house in Buckinghamshire,

the first evidence
began to emerge

of Hitler's secret plot
against the British capital

An elite team of specially
trained intelligence officers

had been posted here to comb
through aerial photographs

taken on reconnaissance missions
over occupied northern France

They were searching for signs
of Nazi weapons sites

Officers examining pictures
of the Mimoyecques area

spotted something mysterious:

railway tracks disappearing
into a hill

They couldn't see
what was going on underground,

but they wondered if the complex
concealed a new kind of weapon

For two years,
a corner of Britain

had already been
on the receiving end

of big Nazi guns

And the K5 railway gun
just outside Calais, in France,

was one of the biggest

It was used for pounding
the English coast, and in fact,

they would quite regularly hit
the town of Dover

Right

And that corner
of southeast England

got pounded so heavily
through the years of the war,

it became known as
Hellfire Corner

What the population would do

would be to run into the caves
in the cliff behind the town,

and the Germans were a bit cruel
in that they would wait

until the all-clear
had been sounded,

until people started
to come out again,

and they'd fire another one

to try and catch them
in the open

They hit the coast very hard

Something like
10,000 houses in Kent

had been destroyed
by this artillery fire

The K5 could fire a shell
40 miles,

but Hitler wanted
to reach London,

more than double the distance

To get there, his engineers
had to find a way

of increasing the speed
of the shell

One method was simply

to increase the length
of the barrel

This kept a bubble
of rapidly expanding gas

from a gunpowder blast
pushing on the shell for longer

But lengthening the barrel
causes a problem

One thing that people
don't necessarily think about

is that this bends
under its own weight

Really?
Even a gun barrel?

Even a gun barrel

And the longer you make it,

the more flexible
it's going to be

But supporting a longer barrel
isn't the only problem

If the barrel
is extended too far,

the expanding gas
propelling the shell

will eventually peter out

One possible solution

was to increase the amount
of gunpowder,

but that would risk
blowing the barrel apart

A German military engineer
named August Coenders

came up with a radical proposal

He would not set off
the whole charge in one go

Instead, he would split it
into smaller amounts

and place them in chambers
along the length of the gun

After the shell was fired
conventionally,

the cascade of explosions would
boost the speed of the shell

as it traveled down the barrel

Hitler ordered his engineers

to build a prototype supergun
in German-occupied Poland,

and stepped up work
on the stronghold

that would house it in France

Then in the fall of 1943,

the Allies took the first steps
to knock out the site

219 bombers took off
from airfields around Britain

The American and British
bombing campaign to destroy

the mysterious building site
at Mimoyecques had begun

In total,
they would fly 18 missions

1,375 aircraft
would drop 6,517 bombs

But conventional bombs
made little impact

on the fortifications
buried deep underground

The Allies were forced back
to the drawing board

Engineers working
on both sides of the Atlantic

tried to find
a powerful enough weapon

to destroy sites like this
in a single blow

The British called on
their go-to engineering genius:

Barnes Wallis

Wallis was an original thinker

with ideas
years ahead of their time

He had designed one
of the most successful aircraft

of World War II:
the Wellington Bomber

But it was the weapon
he invented to destroy

the hydro-electric dams that
powered the Nazi war machine

that made his name:
the legendary bouncing bomb

The success
of the dam busters raid

carried out in May 1943

by the Royal Air Force 617
Squadron

secured Wallis's position as
Britain's top military engineer

Now his challenge would be

to create the biggest bomb
the world had ever seen

and use it
to trigger an earthquake

that would shake
a powerful structure apart

The American military
began experimenting

with an extraordinary innovation
of its own: the drone

The idea was to pack an aircraft
with explosives

and turn it into a flying bomb

A pilot would take the plane
into the air before bailing out,

and then a remote pilot
would guide the aircraft

to the target by radio control

Volunteering
for this hazardous mission

was a 29-year-old naval aviator

He was the eldest son
in a family that would become

a great political dynasty

His name was Joe Kennedy, Jr,

son of Joseph Kennedy,
one of America's richest men

and former ambassador to the UK

Joe's path through life

had already been mapped out
by his family

His grandfather, upon his birth,

had announced to the press
that his grandson would be

the first Catholic president
of the United States

So from day one,
literally and figuratively,

Joe Jr had this focus on him...
That that was his destiny

I mean, it was very much like
an heir to the throne,

the way he was raised

Joe was a naval pilot
patrolling the Atlantic Ocean

on the lookout
for German U-boats

With more than 50 missions
to his name,

he never caught so much as
a glimpse of an enemy submarine

Still, he could have
returned home with honor,

but the chance to lead
the attack on Hitler's supergun

was irresistible

I think he really believed that
this would be his contribution

He didn't think that what
he had done so far was enough,

yet to everyone else,
it was more than enough

But he felt compelled
to keep performing

Neither Kennedy nor his team

fully appreciated the threat
that London was now under

By May 1944,
the Germans were on the verge

of reaching the British capital
with their prototype supergun

They had managed
to fire shells 80 miles

at their secret test site
in Poland,

farther than any other gun
in history

But just how
gun designer Coenders

managed to time
the booster charges

to go off one after the other
with microsecond precision

remains a mystery to this day

One theory is that he used
the hot gases behind the shell

to ignite the boosters

as the shell passed down
the barrel

Engineer Hugh Hunt
wants to test that theory,

so he's asked explosives
engineer Charlie Adcock

to build him a supergun
of his own

They'll use the barrels
of six rifles,

fit each section
with a booster chamber,

and join them end-to-end

If Hugh can get his
experimental model to function,

it will help him
solve the mystery

of how Hitler's supergun
might have worked

There's a couple of things

we want to look at here

One is we want to see
if it was indeed the hot gases

that initiated
the booster charges

And the other thing is,

do the booster charges
make the bullet go any faster?

They'll shoot the bullet

through two beams
of infrared light

The time it takes for it
to pass between them

will give an accurate speed

Here's the live round

First, they'll fire the gun
without the boosters

to set a benchmark speed

We're all good

We can retire to the chamber

Blast on the hooter

Okay, firing!

There we go

That's got a velocity
of 742 meters per second

Now they will try
to speed up the bullet

with the booster charges

Let's load up
these side chambers

So these booster charges,
what have you put in them?

These are rifle cartridges
full of high explosives

Charlie's got
a fantastic instinct

for what's going to work

And handling these high
explosives is a bit scary,

but what I'm most interested in
is whether it's going to make

this projectile go faster

Stand by

Firing!

Whoa!

That's nearly
1,000 meters per second

Hugh has made a key observation

He can clearly see that
the boosters were set off,

as expected, by the hot gas
behind the shell

What have we got?

Everything's fired

Yeah, they've all gone

And as Hugh discovers,
there's an added bonus

There's been a 30% increase
in speed,

and that's going to translate to
maybe a 60% increase in range

In terms of what Hitler

might have been wanting
to achieve with his gun,

booster charges massively
increased the range

And now that Hitler's supergun
was nearing completion,

there was a new urgency
for him to use it

On June 6, 1944, D-day,

150,000 Allied troops
stormed the beaches of Normandy

in the biggest invasion
in history

In just 24 hours, they smashed
through the German defenses

and gained a toehold
in Nazi-occupied Europe

Hitler demanded a rapid response

London was the target

Within a week of D-day,

he had pressed the first of his
vengeance weapons into action

The jet engines
of the V-1 flying bombs

were timed to cut out
over the city

Up to 100 bombs fell
from the sky every day

Over an 80-day period,
about 6,000 people were killed

and a million buildings damaged
or destroyed

The philosophy was that

if you could destroy
the morale of a people,

you would basically
break their will to fight

And so rather than going
for the hard military targets,

you go for the soft
civilian targets

It's a very cruel and it's
a very nasty way of making war,

but they believed it might work

In July 1944,

at a secluded American airbase
in the east of England,

a specially modified bomber
loaded with top-secret equipment

flew in from Philadelphia

This was the centerpiece

of the daring American plan
to wipe out Hitler's supergun

Instead of merely
dropping its payload

on the target from above,

the aircraft itself
would be used

as a remote-controlled bomb

As leader of the mission,

Joe Kennedy chose to downplay
the jeopardy he faced

He writes his father, saying,

"I'm going to stay
just for one more mission

"There's hardly any danger

I'm sure it'll be fine"

And Joe Sr,
while incredibly disappointed,

wrote back and said,

"Please, I understand,
just don't push your luck"

I think he had a sense
of a little bit

of a golden aura about him,

and I think he really believed
he could pull it off

Kennedy's aircraft
would be loaded

with 12 tons of Torpex
high explosives

Then he and his co-pilot would
take the plane up to 2,000 feet,

accompanied by another aircraft
known as the mothership

Using a state-of-the-art
guidance system,

the mothership would
take control of the aircraft

while the crew parachuted out,
itself a risky maneuver

Bailing out
of one of these drones

was very dangerous

because the plane was flying
at very high speed

You might be jumping out

into a 200-mile-an-hour
slipstream

And there were several deaths
that occurred,

and at least one amputation
where somebody's arm

got caught up
in the parachute shrouds

Once the crew had bailed out,
an operator in the mothership

sent a radio signal to prime
the explosives for detonation

They would then explode
on impact

This was the world's first
precision-guided attack drone,

made possible by a piece
of remarkable new technology

What's really amazing,

and I think it's something that
most people don't appreciate,

is before television arrived
in your house,

it had actually already been
used on the battlefield

What we have here

is an actual World War II-era
Iconoscope television camera,

and it's absolutely authentic

It hasn't even been restored

And we've got it hooked up
to a TV monitor,

and I've pointed it
at a somewhat distant object,

an American flag
up on the pole there

Now, I can make out the stripes,
no problem,

but I really can't see the stars
very well at all

But this was good enough to use
for a military application

Adding television
into the system

meant that they could see
exactly what the weapon saw

as it tracked into the target,

and that was
a revolutionary development

The plane was fitted with two
prototype television cameras

One pointed straight ahead,
showing the way to the target

The other was focused
on the gauges on the dashboard

The live pictures
were relayed back

to the operator
in the mothership,

who used a joystick
to manipulate the controls

of the unmanned aircraft

The TV camera made the drone

a truly precise weapon,

something you could fly
by remote control

and see where it was headed,

and you could literally
put yourself

in the cockpit of that aircraft

It was going
to be able to deliver

that 12 tons of Torpex
directly on this target

It was not going to miss

Neither Kennedy's men
nor their British counterparts

had much idea of the scale
of the task they faced

taking on the supergun

Once installed, the barrels
would be encased in rock

over 300 feet thick,

and shielded
by 16 feet of concrete

And so far, the complex had been
impregnable to Allied bombs

But fortunately for the British,

they could call
on the mastermind

behind the bouncing bomb

Barnes Wallis
had already proven his worth

by busting the formidable
German dams

But could he crack a Nazi
stronghold like Mimoyecques?

The thing which runs through
all of his work is efficiency

He was always after
the most efficient solution

to the problem

What he realized was that

it was more efficient
to destroy a factory

than it is to destroy
all of the tanks or airplanes

that come out of the factory,

and it's even more efficient
if you can destroy

the power sources
that the factories were using

Wallis started thinking

about the most efficient use
of explosives

and came up with a brilliantly
original idea:

a bomb that would explode
underground

and create an earthquake

Now Hugh Hunt wants to see
if a bomb going off below ground

would be more destructive than
one exploding on the surface

Well, suppose that this is
a bunker in Northern France

and you want to blow it up

Barnes Wallis's method
was to bury a bomb

deep in the ground
to create a mini earthquake

You only have to push
the foundations a short distance

and you've destroyed
the structure

We're going to do two tests

One test is with some explosive
on the ground nearby,

and then we'll bury
that same amount of explosive

deep in the sand,
and we'll see what happens then

Firing!

Three, two, one!

The pressure has created
a crack in the building

I think it will be
interesting to see,

with the same amount
of explosive, what happens

when we put it in the ground
underneath the building

They bury a second
identical charge

12 inches beneath the surface

Firing!

Three, two, one!

Look at that

Look at how far
the sand has gone

There's ground zero,
and there's nothing there!

It's vanished

That's amazing!

I don't think anybody

had looked at the effect
of bombs exploding underground

at that point

People instinctively thought

it was the bit
of the bomb exploding

that you could see visibly
which did all the damage,

but in fact,
that's only part of the damage

Most of the damage is caused
by the pressure wave,

which is actually invisible

With the help
of slow-motion photography,

it's possible to see
the pressure wave

moving at supersonic speed
ahead of the blast,

rippling the ground
as it travels along

Wallis had found that
above ground,

this wave of energy
would quickly dissipate

and do comparatively
little damage

But below the ground,
through solid earth,

it would travel
with more destructive force

So pound for pound,
an underground bomb

would be more efficient than
one exploding on the surface

But getting it to penetrate
deep into the earth

was the challenge

Each bomb was laboriously
sculpted on a lathe

into the perfect shape

that would allow it
to pierce the ground

and move the earth aside
as it burrowed in

The steel casing had to be thick
where strength was most needed,

but taper away elsewhere
to save weight

So this section down here
is virtually solid,

for hitting the ground very fast
without squashing up

That's really solid

And then it's nice and hollow
down that part

It's only about an inch thick
at this point

And then this would have
penetrated into the ground

to 50 feet or more, and this
would all have exploded,

and the massive shockwave

would have permeated out
through the ground,

and anything nearby would have
been shaken to pieces

The RAF started ordering up
earthquake bombs

It was not a moment too soon

In a dramatic breakthrough,

intelligence officers studying
photographs of Mimoyecques

spotted suspicious openings
in a concrete slab

that protected the supergun's
underground bunker

Just visible
in one of the openings

was an object they identified
as the end of a barrel

It looked like the Nazis had
started installing the supergun

The response from the British
was immediate

The elite 617 Squadron
was called in

Famous for its dam busting raid
with Wallis's bouncing bombs,

the squadron was chosen
to deliver his latest weapon

You were with a group
of really experienced crew,

people who'd been
on the dams raids, you know,

and you looked up to them

And here was a squadron equipped

with yet another
Barnes Wallis weapon

It had to be good

It was that sort of feeling
in the squadron,

that you really got something

with which you could hit
the enemy with

And here was a beautifully
streamlined bomb,

and it really looked as though
it was going to do the business,

like throwing a dart
at the board

and getting a bull's-eye
every time

And this would be
a precision strike

17 bombers, each equipped with
a single Barnes Wallis bomb,

would attack in broad daylight

This rare footage shows
the earthquake bombs exploding

Interpreters examining
photographs of the hill

immediately after the raid

identified eight
enormous craters

made by Wallis's
earthquake bombs

Although the concrete slab
had been hit,

it was impossible to tell

just how much damage the bombs
had done below ground,

so the hill remained
a prime target

One month later,

it was the Americans' turn
to attack the supergun site

Joe Kennedy was ready
to lead the experimental mission

to turn a heavy bomber into
a remote-controlled missile

But as the plane sat
on the apron,

a young officer named Earl Olsen

spotted what he thought was
a flaw in the system

On the control panel
designed to arm the explosives,

a special "safety pin"
had been inserted

This was supposed to prevent
a rogue radio signal,

one that hadn't been transmitted
by the mothership,

from accidentally
arming the bomb

Earl was worried that jamming
the arming panel with the pin

might damage another part
of the system

He took his concerns
right up the chain of command,

but no one would listen

Out of everybody in the field
with the drone program,

Earl Olsen was
the most qualified person

to make an assessment
of this panel,

but he was dismissed

by a number of people because
he was a junior grade officer,

he was not a college graduate,

a lot of what he knew about
electronics was self-taught,

and the people
at the Naval Aircraft Factory

who had built this panel
were viewed as experts,

as world-class experts,

and who was Earl Olsen
to argue with them?

Exactly what the flaw was
that Earl Olsen spotted

has been lost

Finding the one document
that might identify it,

the circuit diagram
of the panel,

has long obsessed Nick Spark

I just kept looking,

and I looked in every
nook and cranny there is:

the National Archives;
contacted the Navy;

and filed Freedom of Information
Act requests

And finally,
after about two years,

in a pile of documents
that I had received,

I turned over a page,

and there it was: a diagram
of this arming panel

So when I saw that, I knew
I had found the smoking gun

Using Nick's diagram,
Hugh Hunt reconstructs the panel

to try to uncover the fault
Olsen had identified

When a radio signal comes in
from the mothership

to arm the explosives,

it essentially powers up
this board, like this

They'd perhaps rather sensibly
put in a safety pin

so that the mechanical
arming system

would never accidentally operate

And if there was a rogue
radio signal like this,

then the lever doesn't move,

which means that the mechanical
arming system is safe

But look,
this light is still on,

and that means
the electrical power

continues to run
to these little solenoids

that are not designed
to have current

flowing into them continuously

The jammed lever
has inadvertently

held down a switch
that allows electricity to flow,

illuminating the bulb
and overheating the solenoid

This could start a fire
and set off the explosives

These tiny components,
called solenoids,

were part of the aircraft's
backup arming system

They would only be activated
if the unmanned drone

ever went out of control
over Britain

and it was necessary
to blow it up in midair

In such an emergency,

the mothership
would signal the arming panel

to send a pulse of electricity
to the solenoids

These would then pull out pins
from the detonators,

priming the explosives to go off

The plane could then be safely
blown up in midair

But if the arming panel
received a rogue radio signal,

as Olsen feared, the jamming
action of the safety pin

would allow electricity to flow
continuously to the solenoids,

and this would cause them
to dangerously overheat

This explains why Olsen
was so desperate

to delay the mission

Before his death in 2011,

he described his final
conversation with Joe Kennedy

Zero hour had arrived

for the drone strike
on Mimoyecques

Joe Kennedy decided
he would take his chances

At 6:00 p m,
he and his co-pilot

squeezed past the 12 tons
of high explosives

and the suspect arming panel

All Earl Olsen could do
was watch and pray

An armada of support aircraft

followed Kennedy's plane
into the air

Olsen was able
to watch the events unfold

as television pictures
from the drone

were transmitted
back to the airfield

Kennedy's plane,
Zoot Suit Black,

had a perfect take-off

It climbed to about 2,000 feet,
which was the mission altitude,

and at that point,
Kennedy went on the radio

and said the code word
"Spade Flush" twice

That was the signal for the
control pilot in the mothership

to take over command
of the airplane,

and he began to test it
methodically:

turning the television
on and off,

putting the plane
into various turns

No one will ever know for sure,

but it seems likely that
sometime after take-off,

a stray radio signal was
picked up by the arming panel,

triggering the chain of events
that Earl Olsen had feared

The aircraft exploded
over England,

almost 100 miles from the target

No human remains were ever found

Joe Kennedy, Sr received
the news the following day

He was devastated beyond words

All his plans, everything
that had happened to him,

he could understand
and he could cope with

But having this happen
to his son

was beyond devastating

To Olsen's deep regret,
his prediction had come true

He had tried so desperately

to prevent them from flying,

and even at the risk
of court-martial

And he was not a drinker at all,

but he got dead drunk
the night that that happened,

and it stayed with him
throughout his life

Joe Kennedy and his co-pilot
Bud Willy gave their lives

to save the people of London

But just 23 days
after their fateful flight,

Allied soldiers made a discovery

that cast the two Americans'
sacrifice in a tragic light

On the 5th of September, 1944,

Canadian troops fought their way
through to Mimoyecques

and found the bunker in ruins

The British attack
the previous month

had destroyed Hitler's supergun
after all

The earthquake bomb
created by Barnes Wallis

had lived up to its name

All of these

carefully constructed arches
of concrete

and all the foundations
for the gun itself

and for the infrastructure
for the gun

was damaged way,
way beyond repair

Many eyewitnesses at the time

described it as being like
an earthquake

In the nick of time,

Hitler's plot to destroy London
had been foiled,

and with it, his hopes
of turning the tide of war

in his favor lay in ruins

The shockwaves
from the American supergun raid

reverberated way beyond
the borders of Europe,

especially for Joe's younger
brother, Jack Kennedy

Jack gets the word
of his brother's death,

this incredible golden brother

who he's adored and revered
since birth,

and yet it also means
something else to him,

and he's very well aware of it

And as he says to his friend,
"Now the burden falls to me"

Jack Kennedy picked up where
his golden brother had left off,

and in 1961 was inaugurated

as the first Catholic president
of the United States

Two years later, at a naval
test site in California,

the president came close
to meeting the man

who tried to save
his brother's life

When John F Kennedy
visited Point Mugu,

Earl Olsen worked there

And people there knew
that he had worked

with Joe Kennedy in the war,
and they said,

"Hey, don't you want to meet
John F Kennedy?"

And he said, "I can't do that

"I wouldn't want to have
to tell him the truth

about what happened
to his brother"

70 years after the war,

bunker-busting bombs are still
part of military arsenals

and drones are in common use

But no nation

has ever successfully deployed
a supergun