Original subtitles

Japan, August 1945,

an event that changed the course of history.

This doesn't look like a larger conventional weapon.

It's something more heinous

and something really to be feared.

In the culmination of a race

for an atomic bomb,

the USA had catapulted the world into the nuclear age.

One of the greatest fears that the Allies during the war

was that Nazi Germany would get its own nuclear weapon.

The Nazis would absolutely have used this new weapon

to win this war,

and it doesn't bear thinking about really does it?

This was the American motivation

for building the bombs in the first place.

It was incredibly important to the Allies

to do whatever they could to try

to stop the Nazis from progressing.

The effort to build this weapon

required the world's greatest minds.

In Germany, one man stood out: Werner Heisenberg.

He was a genius.

He was a German scientist living at the top of his game

in Nazi Germany.

But the German attempt to become

a nuclear power failed, leading to some questions

about Heisenberg's role in the matter.

It's really quite mysterious character.

He's very sort of hard to grasp.

Is he a sympathiser of the Nazi state?

Difficult to say.

He never joined the Nazi party,

But he was so loyal to Germany.

He wanted Germany to win.

80 years on, his motives remain a mystery.

So did he really try to slow things down

or was he trying to make atomic weapons for Germany

Engineers with a beating heart

of the Third Reich forging advanced weapons,

feeding the Nazi war machine

and motivating the masses.

They executed history's greatest horrors.

And yet for some,

their true role would remain hidden for decades.

In September 1941, most of Europe is under Nazi control.

As the war raged across the continent, Werner Heisenberg,

lead figure in the German atomic research programme,

travelled to occupy Denmark.

One of the events in Heisenberg's life during the war

that's had a lot of people debating it

for 80 years was the meeting in Copenhagen with Niels Bohr.

Niels Bohr had won a Nobel Prize for physics

and he had mentored Heisenberg

and they've become really close friends.

They were the two most influential physicists

in the world.

A German working for the Nazis

and a Dane of Jewish heritage.

And it seems like something was said during that meeting,

which potentially had wider repercussions

on the whole outcome of the war.

And it's always been speculated,

what did they talk about?

Their post-war accounts of the meeting differ,

leaving many to question Heisenberg's true motive.

According to Heisenberg's own account,

they take a walk in the park, you know,

away from any prying ears.

And what he cryptically tries to tell Bohr is

that Germany is working on a nuclear weapon.

Now this is a real risk. This is high treason.

Had this been found out, he could have been killed.

Years later,

Heisenberg claimed he was trying to enlist Bohr

to aid in his own efforts to prevent the creation

of nuclear weapons.

But this was not what Niels Bohr recalled.

He claimed the meeting took place in his office

and the intent behind it was radically different.

Bohr's response was, "I don't remember any of that.

What I remember is you came and said,

'Germany is going to win the war,

we needed to cooperate

with the German authorities in Copenhagen.'"

Whatever the truth of the matter,

this meeting likely played a part in accelerating

the USA's nuclear weapons programme, the Manhattan Project.

In 1943, Neils Bohr flees Denmark, ends up in the US.

There he tells his colleagues,

"The Germans are working in atomic bomb.

Heisenberg is working on it."

And Bohr tells them

the message he thought he got from Heisenberg,

that Germany will win the war with nuclear weapons.

In light of a groundbreaking discovery

made in 1938 in Nazi Germany,

this would've been no idle threat.

This is nuclear fission.

A nucleus of uranium 235 or plutonium absorbs a neutron.

It then distorts like a liquid drop.

Eventually it splits into two or three fissile neutrons.

These are new elements and a great deal of energy.

So one fission can become 2, 4, 16, 256.

Now if you slow this process down,

you can produce heat and electricity.

But if you don't slow it down

and you have enough of a critical mass,

this is the heart of an atomic bomb.

News of this discovery spread like wildfire

across the international scientific community.

This was a groundbreaking discovery

because when it became known, many physicists understood

that this immense source of energy could be used as a weapon

because the destruction they reckoned

would be absolutely colossal.

After the discovery of nuclear fission,

isolated scientists wrote to German officials

saying there's a potential for a new weapon here.

The same was happening in America.

Albert Einstein who had fled Nazi Germany

wrote to President Roosevelt

to warn him about the potential of a nuclear bomb.

By the summer of 1939, in Germany,

all research reports were classified.

Army officials started recruiting the top scientists

to work on military applications of nuclear fission.

At this point, Werner Heisenberg became a crucial player

in the Nazi war effort.

He was a genius.

He was a German scientist living at the top of his game

in Nazi Germany.

He was well respected.

He was constantly being invited to conferences.

He was publishing papers.

He was really immersed in the word of physics,

and eventually politics kind of pulled him out of that.

Born in 1901 into a family of academics,

Werner Heisenberg's potential was clear to see

from a young age.

Heisenberg excelled in science and maths

and even music from the word go as a child.

And what he does is to constantly compete against

his brother, who's only a year older than him.

There is one part which is also kind of a constant

in Heisenberg's life, this being competitive.

So he is often trying to be the best.

At the age of 26,

whilst at Gottingen University,

he revolutionised the world of physics

with his principle of uncertainty.

He later received the Nobel Prize.

Heisenberg's life during the 1920s must have been

incredibly intellectually stimulating.

During his time here, he met Einstein

and walked with Einstein through the streets of the town.

He met Niels Bohr

and established a lifelong friendship with him.

He's an absolutely sort of focal point,

a reference if you like, in the world of science

and physics, during what is now known

as the golden age of physics in Germany.

It's his time at the beginning of the 20th century

where there are these huge scientific leaps forward.

But outside the world of physics,

Germany was troubled

and a new radical party was rising to power.

The National Socialist German Workers Party.

Led by Hitler.

I think people of Heisenberg's generation,

those born in very early years of the 20th century,

were ripe for indoctrination by Nazism.

I don't think Werner Heisenberg personally was,

I think he was, if anything, a pure scientist.

He was utterly absorbed in his work.

Heisenberg was apolitical.

He was not concerned with politics.

He did not pay much attention to the Nazis

until they came into power and started doing extreme things.

Almost immediately,

Hitler began introducing laws targeting Jews,

and Heisenberg saw the devastation

this wrought on the physics community.

In total, 20% to 25% of the academic stuff was dismissed,

most of them in the first period of 1973.

This is devastating for the physics community.

So for instance, we have here a picture

of a party at the Kaiser Wilhelm Institute in Berlin.

And I look at this picture

and I know that it's a moment of happiness for everyone.

We have the most well-known physicists in the world here.

But this picture, the happiness that's in it,

is from historical perspective, clouded.

And one of the black clouds is this law of 1933.

Most of the individuals in this image

will have to leave Germany because they're Jewish.

Indeed, all but four people in this image here are Jewish.

What had been an incredible momentum in atomic physics

is halted almost by the immigration

of these physicists to other parts of the world.

As Jewish professors left Germany one by one,

Heisenberg pleaded with them to stay,

arguing that the situation would get better.

Now, we now know that this was a very naive reaction,

but it shows that Heisenberg was deeply affected by it,

personally affected by it,

but also that he really didn't believe that Jews

would have to leave Germany forever.

He thought this was just a wave of unpleasantness

that would settle down.

But as things progressed for the worse,

the German scientific community began

to spread across the world.

And those who were once friends would soon be working

for enemy states.

The beneficiaries of that were countries like France,

England, the United States.

This decimated the physics community,

and Heisenberg sees that happening.

Heisenberg was powerless,

and it wasn't long before he too became a target

of Nazi ideological oppression.

So what we have here is an article from DS (indistinct),

which is an organ of the SS, entitled (speaks German),

"White Jews in the Sciences."

Written by an older physicist,

named Johannes Stark,

it was a violent attack spurred on by jealousy

of Heisenberg's career.

The article is a diatribe against Werner Heisenberg,

and it's devastating for him.

The article explains that being Jewish

is not only those who are of the Jewish religion

or of the Jewish descent,

but also individuals who promulgate Jewish theories

such as Relativity Theory by Albert Einstein

or who have within their company, Jewish citizens,

of which Heisenberg is one.

This was a masterpiece of character assassination

in the Nazi regime.

Stark, in addition, here calls Werner Heisenberg,

not only a white Jew,

but what he calls "Der 'Ossietzky' der Physik."

Now, Carl von Ossietzky was a journalist

who everyone knew was imprisoned in a concentration camp.

So to be called the Ossietzky of physics

was essentially saying Heisenberg belongs

in a concentration camp.

In Hitler's fanatical regime,

such accusations could have grave consequences.

He couldn't sleep.

He had dreams that SS officers come to his flat.

How does Heisenberg respond?

He went on the offensive to defend himself,

and here chance enters the history.

Heisenberg was really quite lucky.

His mother was an acquaintance of Himmler's mother,

and that connection probably saved Heisenberg.

Himmler is, in 1938,

one of the 345 central figures of Nazi Germany.

The most important is, of course, Adolf Hitler.

And then when you look around,

the power system at this stage can argue

that he Himmler is so to speak,

a third of these group of four.

Heisenberg had the opportunity

to appeal directly to the head of the SS.

Heisenberg gave the letter to his mother.

His mother gave it to Himmler mother.

This was not timid. This was not meek.

This was a demand,

"I refused to let people call me this way."

Himmler ordered an investigation

into the matter.

Heisenberg repeatedly travelled

to the Gestapo headquarters in Berlin

for long interrogations.

This was extremely stressful and distressing.

His prestige meant he had the opportunity

to flee abroad.

Yet despite the attacks against him,

he chose to stay and side with the Nazis.

So why on earth is he not taking the opportunity to leave?

Heisenberg was constantly compromising his own position

in the Reich in order to remain in Germany.

He loved Germany. He did not want to leave.

Eventually, after a year long investigation,

Himmler cleared Heisenberg of the allegations.

The SS leader had spotted Heisenberg's potential.

With the war on the horizon,

Germany could not lose its top physicist.

Hellweg uses this phrase, which in German says, literally,

"We can't afford to kill this man.

He wants to work with us. We need him."

September 1939, Germany has invaded Poland.

The war in Europe has begun.

Hitler's ambition was clear,

he wanted to dominate the continent.

To do this, he'd need powerful weapons.

Army officials immediately created the Uranverein,

the Uranium Club.

The Uranverein or Uranium Club was the beginning

of Germany's nuclear programme.

Physicists assembled in order to begin the work

of seeing whether fission could work for a nuclear bomb.

Heisenberg was quickly recruited

to take on a leading role in Germany's nuclear research.

Essentially, he goes from being this kind of pariah

to being most important man in German science.

Heisenberg's invitation to work on the nuclear project

was for him a way to ensure the relevance

of nuclear physics to the Reich.

So far as I can see, there was very little introspection

of creating weapons for the Reich.

Heisenberg's first contribution to the uranium project

was he works out the possibilities

of controlling chain reactions

in what he called a uranium machine.

What today would call a new nuclear reactor.

But to build Heisenberg's working reactor,

they needed a substance vital to the process, heavy water.

And there was only one place it could be sourced.

The main supplier of heavy water in the world,

but it was on the order of tiny amounts,

was a power plant complex in Norway

called the Norsk Hydro.

The German was not interested in power plant itself,

but they were interested in these cells.

This is the high concentration cells,

which was used in the last steps

of the heavy water production.

Discovered a few years earlier,

heavy water is found in normal water,

but only in microscopic quantities.

And the process of extracting it is extremely difficult.

They used brute force

and massive amounts of electricity,

essentially repeatedly boiling the water

to separate the heavy water from regular water.

Heavy water looks like, tastes like, and smells like

ordinary water, but it's 10% heavier,

and that is because it contains heavy hydrogen

instead of common hydrogen.

If you water a flower with heavy water

instead of normal water, it'll grow slower.

Heavy water could slow down

the neutrons produced by nuclear fission

and thereby control the chain reaction.

And it became crucial to Germany's nuclear research programme.

After Norway was invaded in 1940,

the Nazis had complete control over the world's main source.

The fact that the Germans are interested in heavy water,

which has no other obvious military application,

it very much frightened Allied officials

and Allied scientists.

It's essentially saying we are working on an atomic bomb.

In time, the Allies would have to react.

So the Vemork becomes this centre of intrigue

and this centre of, okay,

we don't know exactly what's going on in there,

but whatever is going on, we need to destroy it.

Back in Germany,

Heisenberg and his team of scientists were progressing

on their secret research.

He's certainly participating in advancing

the use of nuclear fission to create

what he called Uranium Machine.

But when you look at what Heisenberg was doing

during the period 1939 to 1945,

he is not devoting all of his energy to this project.

He is still maintaining his activities at the university.

Beginning in 1940, he begins

to receive many different invitations to travel abroad

and give popular lectures on science.

Heisenberg was renowned internationally.

As such, he was sent across Nazi territories

to promote German culture abroad.

It was during one of these foreign trips

that the controversial meeting with Niels Bohr took place.

Heisenberg was supposed to give talks, have a conference,

and the scientists at Niels Bohr's Institute were invited,

and it would've been open public collaboration

with the Germans in Copenhagen.

And Bohr and his colleagues refused to go.

Heisenberg urged Danish colleagues,

"You should cooperate with the Germans."

This disturbed Bohr very much.

Denmark was under occupation,

but Heisenberg couldn't recognise the position

that left him in.

Whatever his feelings on the matter,

he appeared as the scientific face of the regime,

and this brought the attention of the Allies.

These foreign lectures were ambivalent

because outside of Germany,

everyone perceived him as a representative of Nazim.

This was inevitable.

He may have made a distinction in his own mind,

"I'm representing Germany, not Nazim,"

but his colleagues in occupied countries

could not see that distinction.

Heisenberg invariably said things that disturbed them.

He invariably repeated the propaganda line

of the German government.

He defended the German war effort

and he said Germany should win the war.

But he never indulged in antisemitism.

And that's striking

because it was so easy

to opportunistically use this language

for one's benefit in the Third Reich.

But in the end, Heisenberg got on well with leading Nazis

because he was willing to work with them

on things they considered important.

His complex relationship with the state

was difficult to understand for his foreign colleagues.

But within the context of the war,

Niels Bohr was convinced

Heisenberg was committed to the Nazi effort.

And it was a worrying state of affairs for the Allies.

Fear of a German atomic bomb was mounting.

By 1943, the United States believed

that Germany was making some progress on atomic science

and perhaps building their own bomb.

Determined to beat the Germans to it,

the US government created the top secret Manhattan Project.

The race had begun.

It was a massive international project.

The three main centres in the United States

were Oak Ridge, Tennessee, Los Alamos, New Mexico,

and the Hanford, Washington.

They knew of the potential of nuclear power.

They recruited scientists from all over Europe

as well as America itself to work on this secret project.

They had basically a blank check from Congress.

They needed money, Congress was not allowed to ask what for,

they just had to give it to them.

Over 120,000 to 130,000 people worked on this project.

There is awareness that the first people

to create this new kind of weapon,

they are gonna have an absolute advantage in this war.

And so it was incredibly important to the Allies

to do whatever they could to try

to stop the Nazis from progressing.

The Allies targeted key locations,

and the Vemork was crucial to the German atomic programme.

But two years of aerial bombing missions had failed

to have a significant impact on heavy water production.

In the winter of 1943,

Allied leaders decided on a new approach.

They find out that actually just trying

to kind of bomb the outside of the plant

is actually not gonna help very much,

'cause what they figure out is

where a lot of the heavy water is being dealt with

is actually underground.

The only solution was to destroy the plant

from the inside.

The Nazis are then very aware of the fact

that actually this is a place of interest for the Allies,

which directly feeds into how difficult

that final sabotage mission is gonna be.

In February 1943,

Operation Gunnerside was launched.

Nine saboteurs parachuted into the Norwegian mountains.

Their mission was to infiltrate the plant.

They managed to make their way into the building

without being seen by the patrolling guards.

They crawled over the pipes

and jumped down on the floor in the room

beneath where the heavy water cells were placed.

This room was a target of Operation Gunnerside.

On this wall, it was heavy water cells.

Mission was to place charges on each of the cells

and blow them up.

Working against the clock.

Detonators were placed on the 18 heavy water cells.

By the time the Nazi guards rushed to the site

of the explosion, the saboteurs were gone

and the heavy water cells had been destroyed.

To what extent did it actually stop

the Nazi atomic programme?

It certainly slowed down the progress of the programme

at that particular time.

This was a setback for Heisenberg

and his team of scientists in Berlin.

But the Allies were not just targeting

production facilities,

they were also targeting key individuals.

The United States were determined to stop

those German scientists,

either go and find them, capture them,

or kill them if necessary.

Their main focus was Heisenberg.

Now, according to some accounts, they got some intelligence.

Heisenberg was giving a lecture in Zurich.

So what they did is that they sent a spy,

someone who could speak German.

The name of the spy was Moe Berg,

a former baseball star

with a knack for languages and an interest in physics.

On the 18th of December 1944, Berg actually goes to

that lecture and in his pocket he's got a pistol.

And he had very specific orders,

if there was an indication that the Nazis were close

to building a nuclear weapon, he was to shoot Heisenberg.

Heisenberg doesn't say anything about a bomb,

doesn't say anything about building a weapon.

Moe Berg then gets himself invited to a dinner party

where he gets to sit and listen and ask more questions.

He did such a good job of playing his role

that Heisenberg actually thought he was an SS spy

checking to make sure he wasn't telling any state secrets.

Heisenberg was unaware he'd had a lucky escape,

and for now, the Allies remained in the dark

about the progress of the German nuclear programme.

In early 1945, the end was near for Nazi Germany.

From the west, despite some harrowing battles

and the harsh winter conditions,

the Allies progressed further into Germany.

From the east,

the Soviets were closing in on Hitler and his army,

but as the Allies gained territory, the focus was shifting.

This understanding that there's going to be tension

or conflict between the United States

and the Soviet Union really intensifies the need

to control German technology.

So all of a sudden, you have a race to see

who can acquire the most territory

and who can save the most scientists for their own side.

As part of the Manhattan Project,

a scientific intelligence gathering mission

called the Alsos Mission was created

and followed immediately behind the advancing Allied armies.

The task, search for evidence

of a German atomic bomb project,

and if necessary neutralise it.

After making their way across Europe,

the Alsos mission progressed into Germany,

capturing scientists and nuclear material along the way.

But they were after a bigger prize.

The Alsos Mission considered Werner Heisenberg

prisoner number one.

He absolutely had to be gotten in order to find out

what the Germans had done,

how far they had worked on their atomic bomb project.

He had to move from place to place.

The scientists in Germany were not secure

in the work that they did.

They had bombing, they had invasions,

they had the actual war was in their space.

Secret reports located him

near a place called Heigerloch.

Heigerloch is a small town in southern Germany.

It's in a valley with a river running through it,

and it's got cliffs all around it, so it's very secure

and very hard to get into

In a hidden beer cellar

carved into the side of a cliff,

they found what they were after:

a secret nuclear laboratory.

When the ALsos Mission arrived,

it appeared as if the lab had been raided.

Just days before,

the German scientists had dismantled the reactor

to keep their work secret from the enemy.

The Americans could not risk leaving empty handed.

They searched the area to identify

and round up the remaining scientists who cooperated.

With the help of the German scientists,

they found the buried uranium, the hidden heavy water.

They found the scientific reports,

but what they essentially found

was that this was an incomparably,

smaller, tinier scale

than the American Manhattan Project.

That it was simply not comparable.

And so the idea that there could be any threat

of a German atomic bomb was absurd.

They had these ideas and these fears

that this great German scientist was making

these very threatening advances,

and it was just so underwhelming

to find this very small reactor.

While the fear of the Nazis gaining access

to an atomic bomb had driven the Allies own efforts,

the reality was that Hitler had missed

his opportunity a few years before.

If you want to compare the German

and the American atomic bomb projects,

the turning point is summer, fall of 1942.

Late spring 1942,

you could make the case that the two sides

are pretty comparable.

But Hitler's failed military operations

in the East had weakened Germany.

The change in fortunes of the war

had a profound immediate effect on the uranium project.

Army ordinance asked the scientists,

"When can we expect these weapons?"

The scientists responded,

"Nuclear weapons are feasible.

It's unlikely that it can be done during the war."

As a result,

funding for the project was capped.

And despite the fears of the Allies,

it never went further than a theoretical programme.

Very many leading Nazis all spoke about

these fantastic new weapons that would turn the tide,

win the war for Germany.

The irony is that about the only wonder weapon

that Hitler didn't talk about

and didn't really pay any attention to

was the atomic bomb.

If Heisenberg had said to Hitler,

"Mein Fuhrer, I have got the power

to unleash the the forces of nature in a nuclear blast.

With this weapon, we can win the war."

If he had been that sort of man,

then the war might have had a completely different outcome,

but he wasn't fortunately,

The threat of a German bomb was gone,

but the Allies still needed to locate their prime target.

Heisenberg in quite dramatic fashion,

in the last days of the war,

rides on his bicycle across war-torn southern Bavaria

to be with his family.

He manages to reach his family.

And he's only there a day or two,

and suddenly American soldiers burst into his house.

At the same time, there are SS men outside his house

and there's a fire fight.

Eventually the Americans dispersed

the German soldiers

and got their hands on Heisenberg.

He had to be arrested

because they were afraid that the Russians would get him.

Heisenberg and nine other scientists

were brought to England

and imprisoned in a safe house called Farm Hall.

They had three square meals a day.

They were allowed to play chess.

The conditions at Farm Hall were pretty cushy

in comparison to prison camp.

For months, the captives were unaware

that the house was bugged.

All of their conversations were recorded in the hope

of uncovering more secrets about the Nazi nuclear project.

The United States was keen to learn

where the Germans were at

because this was the American motivation

for building the bombs in the first place.

Hiroshima, after the atomic bomb blast,

that virtually erased this city

of 340,000 people from the earth.

The Allies were also intrigued

to see the scientists response to the news

of the Hiroshima bombing.

Their reaction was unexpected.

They were shocked.

In fact, they were awed at the production of a bomb.

Perhaps the Germans suddenly realised

something they hadn't before.

They had been in a race against the Americans

to build a nuclear weapon, and they had lost.

I think if you study Heisenberg, if you read about him

and you read about what other scientists said about him,

he was very smart.

He was very competitive too,

and I think a bit arrogant is how he comes across.

Heisenberg and the other scientists

at Farm Hall were now faced with a dilemma.

They had worked on a weapon of mass destruction

for the perpetrators of the Holocaust,

and they needed to protect their reputations

both at home and abroad.

That's not a particularly comfortable situation to be in.

So how do you handle this issue?

You can't just say, "We sabotaged the work,"

that would be betraying Germany

As a patriot,

Heisenberg was unwilling to be seen as a traitor,

which created another dilemma.

You can't just say, "Well, we couldn't figure it out."

That makes you look incompetent.

So by looking at the future like that,

they begin to construct a narrative, a moral narrative,

an outrageous one in most people's view.

You begin with an accurate statement.

It was not possible for Germany

to make nuclear weapons during the war.

You then bring in the legend of Copenhagen

and say that, "We travelled to Denmark

in order to enlist the help of Niels Bohr

so that we could forestall the creation

of all nuclear weapons.

We wanted to save the world from nuclear weapons."

Not just stop the German ones.

That's malarkey. That's complete malarkey.

I mean, they're trying to save their post-war lives.

For me, what's really interesting

with Heisenberg is that he's always forced

to find a way through a complicated situation

and he was very successful in not being too clear

and too open.

I think he just lost,

and it's much easier to admit

that you were actually the good guy

trying to save the world than it is to admit

that the other side won.

After months in captivity,

the scientists were finally released

and Heisenberg returned to Gottingen.

He and his colleagues author what is known

as "The Gottingen Manifesto."

They commit themselves

to never working on nuclear weapons again.

He's finally coming to terms

with some of the moral questions that he should have raised

during his time with the German atomic bomb project.

Perhaps Heisenberg was aware that he had helped

to set the wheels in motion.

The race to build the atomic bomb absolutely shaped

the history of the world after this war.

The atom bomb actually was the beginning

of a race to develop deadlier and deadlier

and deadlier weapons

Against the dark background of the atomic bomb,

the United States does not wish merely

to present strength.

To this day,

the United States of America is the only country

to have used nuclear weapons in war.

But the latent threat has been ongoing

for decades across the world.

The nuclear legacy of the Second World War is a war

where we're in possession of the means

of the destruction of humanity.

We still have 14,000 nuclear weapons

on the face of the earth, most of them in the hands

of the United States and Russia.

Remember, the five permanent members of the Security Council

of the UN are the original five possessors

of nuclear weapons.

They have a privileged position within the United Nations.

Germany never developed atomic weapons,

although they hadn't built a working nuclear reactor

in time for the war,

Heisenberg and his colleagues had actively participated

in driving the world into the nuclear era.

Without the German Uranian project,

there's no American atomic bomb.

There's no nuclear arms race right after 1945.

The world would've been a very different place.