Legends say there's a world beneath this one, where a dragon lies sleeping.

They say be careful how you wake the dragon.

Around the turn of the 20th century, uranium is almost unknown.

It is basically worthless.

But, then, in 40 years, just a single generation, it becomes the most desirable and terrifying rock on Earth.

This is uranium.

And, as a physicist, I'm fascinated by its unique scientific properties, but, even more so, by how this one rock has shaped the entire modern world.

Uranium changes everything.

Aaaaaaah!

MULLER: Uranium makes the modern world.

Uranium is a dream of clean, limitless power or a nightmare of a silent and poisoned Earth.

Come with me on a journey to find the most desirable -- This is a nuclear reactor.

And the most hated rock on Earth.

-It's just that fear: if it blows, what's going to happen to us?

MULLER: How did we unleash the elemental force within uranium?

What happened when we woke the dragon?

This is the story of how a rock became a bomb.

"Uranium: Twisting the Dragon's Tail" This ancient land is home to the indigenous Australians, the oldest continuous culture on Earth, and they say that, at the time of creation, a spirit being, a great reptile, formed this land and everything else on Earth.

And then, it went underground, where it still sleeps and mustn't be disturbed.

Now, we know that, beneath this soil lie some of the richest deposits of uranium anywhere on Earth.

And uranium is like a sleeping dragon.

It's a beast of mythical power.

Now, the traditional owners of this land say that, if you disturb this place, you will wake that sleeping spirit and unleash disaster.

In 1945, the power of uranium is unleashed on the city of Hiroshima in a single bomb.

How does a rock dug from the earth contain such power?

I was born here in Australia.

I studied physics here and the story of the great power beneath the earth intrigues me.

I want to follow the story of uranium.

[echoing] At a time of creation, before there's an Earth, a star explodes, a supernova.

In the incredible violence and heat, uranium is forged.

Uranium crackles with the energy of an exploding star.

From the debris of the explosion, 4.5 billion years ago, our Earth forms and the uranium is embedded into a hot and molten Earth.

The Earth cools with the uranium inside, still crackling with the energy of that exploding star.

I've come to the Czech Republic, the first step on my journey to find uranium.

These are Geiger counters.

They measure nuclear radiation: tiny particles emanating from the remnants of that exploding star.

Each time they detect radiation, they make a sound.

[Beeping] Radiation exists naturally everywhere on Earth.

Here in the Czech Republic, the level is about 0.2 microsieverts per hour, which is about average globally.

Now, over the course of the day, that adds up to the same amount of radiation you receive when you get a dental x-ray.

Radiation is in the air you breathe and the food you eat.

It's in the soil and it comes from space and that is due to the tiny amounts of uranium and other radioactive atoms found all over the planet.

Every person, including you, emits nuclear radiation, so, you're exposed to more if you sleep next to someone than if you sleep alone.

This is completely natural.

It's called background radiation and it's just part of being alive on planet Earth.

Natural background radiation varies all over the Earth.

I'm measuring it in units called microsieverts.

But the thing to remember is that natural background is about 0.2 microsieverts per hour.

But the reason I've come to Joachimsthal isn't in the town; it's in the hills nearby.

This is a 500-year-old silver mine.

That's what they did in Joachimsthal: they mined silver.

But this is where our story of uranium begins.

We're descending at about 3 meters per second and we've been going, now, for about 3.5 minutes, and still going.

My ears keep popping 'cause of the change in pressure.

[Tone] -[ Alarm pulses] There must be some uranium ore around here 'cause I'm reading about 5 or 6 microsieverts an hour.

That's something like 50 times the background that we'd normally be exposed to on the surface.

[Horn blares] We've arrived.

Joachimsthal Mine, bottom floor.

[Water dripping] I'm looking for a dark seam of rock.

Yeah, here it is.

This is the stuff that the silver miners hated because, when they found it, it meant that the silver seam had played out.

So, they nicknamed this rock pitchblende: pitch, which means "hard luck" and blende, meaning "rock".

So, this was the hard-luck rock.

But watch what happens under ultraviolet light.

It fluoresces.

There's a German chemist in 1789 who analyzes this stuff and finds that there's a new element in there and he names it after the recently discovered planet Uranus and, so, the element becomes uranium.

Getting a lot of radiation coming right off this pitchblende.

Remember, up at the surface, the background level was 0.2; this is 4,000 times that level.

This is the energy forged in an exploding star.

For about 400 years, the hated pitchblende that contains the uranium is thrown away.

The worthless pitchblende is dumped in these great, big piles about the mines, unlike the silver, which makes the town rich.

They mint these big, silver coins, joachimsthalers; it's the origin of the word "dollars" and, come the 20th century, all of this bad-luck rock is going to be worth a lot of dollars.

Uranium may have remained underappreciated in the slag heaps of Joachimsthal, were it not for the curiosity of a 43-year-old physicist here in Paris.

In 1896, Henri Becquerel is professor of physics here at the Ecole Polytechnique in Paris.

It is in this building that he performs an experiment to explore the florescence of uranium and what he finds is something incredible.

At the time, the only known use of uranium is in glassmaking: to make a pale, yellow glass which sparkles in sunlight.

But, again, watch what happens under UV light.

The uranium glass fluoresces and it's this that fascinates Henri Becquerel.

It leads him to perform a groundbreaking experiment.

He takes an ordinary piece of photographic film and, in complete darkness, he wraps it in thick black paper.

And then he puts a piece of uranium on top and leaves it out in the sunlight for several hours.

When he later develops the film, he finds that it's been fogged, as if it's been exposed to a burst of sunlight.

So, Henri reasons that the uranium is actually absorbing the sunlight and reemitting it as invisible rays which penetrate the black paper and expose the film.

[Thunder rumbles] But the real discovery comes courtesy of the fickle Paris weather.

Thursday, February 27, 1896, should go down as the most famous overcast day in the history of science.

Henri prepares his experiment exactly as before, but, there being no sunlight, he puts it away in a drawer, where he leaves it for several days.

And then, for no reason anyone can ever really explain, he decides to develop the film, anyway, even though the uranium was never exposed to sunlight, and what he finds astounds him.

The film has been fogged, just as before.

But how is that possible, without the sunlight to energize the uranium?

Well, there is one answer and it's seriously weird: the sunlight has nothing to do with it.

[Thunder rumbles] Henri has found a strange, unknown energy, and it's coming from inside the uranium.

Now, one of Henri's students is Marie Curie.

She's brilliant and she's going to win two Nobel Prizes but, for now, she's looking for a subject for her doctoral thesis in physics.

She decides to study the strange energy in uranium, which she gets for free from the piles of pitchblende lying around the old Joachimsthal mines.

This is Marie's laboratory.

They've now removed almost all of the radioactive material that used to be here, but this door leads to Marie's office, so, she would often place her hand, after working in the lab, on this doorknob and you can still detect traces of the radioactive material that she left right on this door handle.

But it's so little that it's not dangerous.

This is an incredible old Geiger counter they had lying around here at the Curie Museum.

Now, listen to this.

-[Crackles] This is pitchblende, an ore containing uranium.

[Crackling intensifies] This is what Marie Curie starts with.

Now, over painstaking years, she manages to grind down this substance and extract the uranium.

But what she finds surprises her.

The uranium isn't the most active thing in the rock.

In fact, there are other elements, which are even more unstable and spit out even more energy; the most famous is radium.

This completely new element, radium, glows, it's warm, it releases strange, wondrous energy.

It is Marie's husband, Pierre, who first notices that, when he places a glass vial of radium against his skin, he develops a little sore, like an intense patch of sunburn.

To us, this suggests danger, but physicians of the time had been treating various skin diseases and tumors by burning them, so, perhaps, this could be the perfect application for the new wonder element, radium.

The doctor has to urge the girl to turn.

MULLER: Glass vials containing radium are sewn into bandages and applied directly to tumors.

It's applied to affected ar ea of the skin and fastened with bandage.

The process of the radiation has begun.

The rays penetrate into the tumor and destroy it.

The children usually play games, forgetting all about the treatment, which is quite painless.

Several months have passed an d the girl is brought to see the doctor once again.

Look this way, Marina, dear.

When you grow up, you'll be very thankful to those who, at the very dawn of the Atomic Age, cured you with these magic rays.

The only way to get radium is to process uranium ore.

In fact, it takes 7 tons to make just 1 gram of radium.

How can it possibly be worth it?

Well, in 1908, gold cost 66 cents a gram.

A gram of radium is worth... Radium is put into expensive cosmetics, soap, toothpaste, tonic water.

It's seems a wondrous cureall, exploited even by the town that once considered it worthless.

The old mining town of Joachimsthal, the place that invented the dollar, reinvents itself as a health spa.

"Come and bathe in radium."

Well, as you can see by the atomic logo on my robe, I'm about to get into a radioactive bath.

This is the first time I've ever done anything like that.

[sigh] Let's see what this feels like.

Ahh.

That's actually quite comfortable.

The bath is set at about 36° Celsius, so, it's quite comfy.

Now, there are dissolved radioactive particles in this bath.

I'm going to see if I can pick up any of that radiation.

Oh, that's interesting.

My counter is reading significantly more radiation than when it was in the air.

As I bring the Geiger counter down over the water, I can see the level is about 1.5 microsieverts an hour.

That's about 10 times the background radiation in this town.

The idea is that this water will seep through my skin, along with some of those radioactive atoms, which will then emit their radiation in my body.

And the idea is that should reduce some inflammation; that's radiation therapy, in short.

But I think the dose here is so low that I don't have to worry about good or bad effects, so, for now, I'm going to kick back and enjoy it.

The radium spas attract a wealthy clientele, including, in the summer of 1921, a precocious 17-year-old American: Robert Oppenheimer.

He's fascinated by the rocks lying around from the old Joachimsthal mines and in 20 years, Robert Oppenheimer will ensure that uranium becomes the most terrifying stuff on planet Earth.

[Foreboding music plays] Because young Robert Oppenheimer is going to make uranium into the bomb that explodes over Hiroshima.

Paris, in the year 1903.

Radium makes Marie Curie the first superstar of atomic physics.

And it is for the study of this rock that Marie Curie is awarded her doctorate in physics, the first woman, ever, in France.

To celebrate, she and Pierre hold a party out in the garden.

[Piano plays] And we're all invited.

[Laughter] In the garden that night, Pierre Curie pulls from his pocket a vial of radium and everyone gasps.

In attendance is a 31-year-old New Zealander, Ernest Rutherford.

He wonders "What makes this stuff glow and what is the relationship between radium and uranium?"

Rutherford had partnered with a brilliant 22-year-old chemist named...

Together, they've been studying uranium and it's taken them on a journey into the tiny, unknown world of the atom.

A spec of uranium, the size of the dot over an i, would contain more than 2 million trillion atoms.

[Warbling] -[Suspenseful music plays] The heart of the atom is the nucleus, 20,000 times smaller than the atom itself.

This tiny nucleus at the center of the atom is made of protons and neutrons and they're tightly bound together.

Unlike billiard balls, protons and neutrons can't be knocked around.

They remain fixed, unchanging, inside the nucleus and it's actually the number of protons inside each nucleus that defines the element.

An atom with 1 proton as its nucleus is the element hydrogen.

In the atomic world, it doesn't get any simpler.

Every atom in the universe with 1 proton is hydrogen.

An atom with 2 protons is the element helium.

Now, you'll notice this one also has 2 neutrons, represented by white balls.

Now, some helium atoms have 1 neutron, some have 3, but all helium atoms have precisely 2 protons.

An atom with 6 protons is the element carbon.

It could be the carbon in a tree or the carbon in diamond; all have exactly 6 protons.

Each different element has a unique number of protons.

7 is nitrogen.

8?

Oxygen.

79 is gold.

But have a look at this.

The uranium nucleus has a whopping 92 protons and usually 146 neutrons.

It is the biggest nucleus on Earth, so big that it is groaning under the strain.

And Ernest Rutherford and Frederick Soddy find that it is doing something extraordinary: it actually spits out chunks of itself and these chunks are radiation.

Now, they contain protons, so, when uranium releases radiation, it's losing protons, so it no longer has 92, and that means it's no longer uranium.

It's a completely different element!

Ernest Rutherford and Frederick Soddy are witnessing the uranium nucleus transforming itself and this challenges our fundamental understanding of the physical world.

A nucleus doesn't just change, so, this suggests the dark and magical arts of the alchemists.

[Mysterious music plays] Alchemists were wizards and magicians.

They dabbled in potions and spells.

Their dream was to transform one element into another.

They called it transmutation.

The alchemists never succeeded.

It's impossible.

One element can't just change into another.

That's magic.

But, as Ernest Rutherford and Frederick Soddy begin to look at uranium, that's exactly what they find.

They've glimpsed the dragon.

Uranium, when it exhales radiation and energy, transforms into thorium.

It actually turns into a completely different element.

Uranium is a shapeshifter and it does this naturally.

A lump of uranium will do this all by itself.

Frederick Soddy is so excited, he shouts "Rutherford, this is transmutation!"

And Rutherford snaps back "For Christ's sake, don't call it transmutation!

They'll have our heads off as alchemists."

Thorium is radioactive, too.

It exhales radiation and transmutes into protactinium, a completely different element, again.

Rutherford calls these newly formed elements daughters, the daughters of uranium, and each daughter, in releasing radiation, changes into a brand-new daughter.

Radium appears, Marie Curie's radium.

It is uranium's great- great-great-granddaughter.

That's why it's found in uranium ore. Now, radium transmutes into her daughter, radon, which happens to be a gas.

Radon transmutes into her daughter, polonium, which isn't a gas.

And polonium transmutes into her daughter, and her daughter.

Uranium gives rise to 14 generations of change, a line of 14 daughters, and the last is lead.

It's a barren daughter.

Lead isn't radioactive at all; it doesn't transmute into anything.

Lead isn't going anywhere.

Ernest Rutherford and Frederick Soddy have solved one of the great mysteries of radioactivity.

It's uranium transforming itself into lead.

Uranium is doing something no one ever thought possible: it's changing its atomic structure and with each change, it releases energy.

Uranium now gives physicists a novel idea: if someone could find a way to force uranium to change, release all that energy, that person would possess a fantastical power.

[Bells toll] In 1905, here in Bern, Switzerland, lives a 25-year-old draftdodging underachiever.

He has a young wife and an infant son to support, so he needs a job, any job.

And this?

Is his house.

The young man works as a clerk for the patent office.

He describes himself as a "respectable federal ink pisser."

Despite his job, he manages to find time to pursue his main interest: thinking.

The young man's name is Albert Einstein.

Right here, he formulates the most famous equation in all of science...

The equation means that energy, E; and mass, m; are interchangeable.

They're basically different forms of the same thing.

And c is the speed of light, a humongous number.

So, mass times a humongous number squared will give you a tremendous amount of energy.

So, this equation means that a little bit of mass can be converted into a lot of energy.

Every time uranium changes its atomic structure, a tiny bit of mass is lost; it's converted into energy.

According to Einstein, it's a tremendous amount of energy.

Frederick Soddy, the young chemist working with Rutherford, is the first to speculate about this energy.

as SODDY: The man who puts his hand on this store of energy would possess a weapon by which he could destroy the Earth if he chose.

[Bells toll] -The man who imagines a world where Frederick Soddy's weapon becomes a frightening reality, exploiting Einstein's equation of mass and energy, is neither a physicist nor a chemist, but a novelist.

Herbert George Wells writes The World Set Free, a novel in which scientists have learned to harness the power of atomic energy.

[Suspenseful music climbs] 2036 AD.

You are catapulted through centuries, whirled into the great unknown, into an era of glass cities towering to the Sun.

Remarkably, HG Wells publishes his novel The World Set Free in 1914.

He dedicates it, not to Albert Einstein, but to Frederick Soddy.

The book also introduces a new and disturbing term into the language... [Bell tolls] [Foreboding music plays] In 1933, here in London, there is a Hungarian physicist named Leo Szilard.

He's imaginative, driven, impatient, and brilliant.

Now, he has read HG Wells's novel The World Set Free and... it's got him thinking.

Leo Szilard is walking down this street when he stops here, at the corner of Southampton Row and Russell Square.

It is at this intersection that he has the single most dangerous and defining idea of the modern world: what if it were possible to create the atomic bombs envisioned by HG Wells by forcing atoms to convert their mass into energy?

Szilard's idea is to have 1 atom release its energy, triggering more atoms to release more energy, in an exponentially increasing cascade, until a gazillion atoms are all converting their mass into energy simultaneously.

By the time Leo reaches this point, he has the whole terrifying idea in his head, the idea of the chain reaction.

And it's September 12, 1933.

In Germany?

Adolf Hitler is chancellor.

[Cheering] The Nazis are frighteningly powerful, murderously intolerant.

Jews, in particular, are persecuted.

[Crowd chanting] Many of the leading physicists in Europe are Jewish and many flee to America.

Among them is Albert Einstein.

And, in 1938, Leo Szilard joins him from London.

In New York, I'm meeting Spencer Weart.

He's a physicist and historian and I'm here to ask him about Leo Szilard.

-Szilard was a Hungarian; he was a Hungarian Jew and this meant that, from a very early age, he was filled with anxiety and worries about doom and world disasters, and so forth.

Germany, of course, was, at that time, the premier scientific power, and Szilard recognized that, if there were to be an atomic bomb, Germany had a good chance of being the first one to get it, and Germany meant Hitler and the Nazis.

-Leo Szilard's anxiety about Germany developing an atomic bomb gets worse when, in 1939, disturbing news reaches him from Berlin.

At the Kaiser Wilhelm Institute, there's a brilliant German chemist, Otto Hahn.

Now, he'd actually been a student of Ernest Rutherford's around the time that Rutherford and Soddy found that uranium naturally changes its atomic structure.

Otto Hahn has taken the next step.

He's been experimenting with forcing the uranium atom to change and he's getting puzzling results.

He sends his results to his Jewish colleague Lise Meitner, who, by this time, like many Jewish physicists, had fled Germany, and it's Lise Meitner who figures out what Otto Hahn has done.

He split the uranium atom, something nobody thought possible.

Now, when we say "splitting the atom," what we really mean is splitting the nucleus.

Splitting an atom is often presented as a break at billiards, but it's actually much more subtle than that.

Only one particular type of uranium nucleus will split, one with 92 protons and 143 neutrons.

Added together, that makes 235, so it's called uranium-235.

The force that holds the nucleus together is the strongest force in the universe, so, physicists cleverly call it the strong nuclear force.

But the uranium nucleus is so huge, it's under incredible strain, it's unstable and, if I add just 1 more neutron to that nucleus, it increases that instability, so that the whole uranium nucleus rips apart!

It fissions.

And, now, the strong force compacts both of those pieces, so that, overall, their mass is less than the mass of the original nucleus.

Mass has been transformed into energy, just as Einstein said it would.

And, even more importantly, this fission releases 2 or 3 neutrons.

And this where Leo Szilard's idea of the chain reaction comes into play, because if these neutrons go on to hit other uranium-235 nuclei, they cause them to fission, releasing more energy and more neutrons.

So, 1 uranium nucleus can split 2, which split 4, and then 8, and then 16 and, within 60 steps, a quintillion atoms have fissioned, each one releasing energy!

E=mc2 now has a terrifying practicality: uranium can make a bomb.

And the Germans know how to do it.

Adolf Hitler broke the pledge he made at Munich.

He took over all the rest of Czechoslovakia.

The Nazis now control the old mining town of Joachimsthal and, now, they've got both the uranium and the knowledge to make a bomb.

Between Otto Hahn splitting the uranium atom in Berlin and the Nazis now controlling this, the only source of uranium in all of Europe, Leo Szilard is incredibly concerned.

-Szilard was very afraid the Nazis would get the atomic bomb.

He knew that, if they got the atomic bomb well ahead of everybody else, they'd win the war and he was concerned for the future of Western civilization, so, what could be done about it?

He had to get the United States working on it and that meant President Roosevelt, so, Roosevelt should know.

Well, how is he, Leo Szilard, going to get Franklin Roosevelt's attention?

-In New York, Leo isn't famous enough to get a letter to the president himself, but he has a friend here who is.

Albert Einstein is now the world's most famous scientist.

These days, he rents a beach house for the summer on Long Island, New York.

Leo goes to see Albert and he tells him about his frightening idea for the uranium bomb.

And Albert has never thought about this before, but he does now, and the implications frighten him, too.

So, Albert puts his name on a letter to President Roosevelt, warning him that the Nazis might be working on a uranium bomb.

Roosevelt now orders research to begin on an American uranium bomb.

[Suspenseful music climbs] ROOSEVELT: December 7, 1941, a date which will live in infamy.

-In 1941, America is at war with Germany and Japan.

American industrial might is turned to war.

Leo Szilard's uranium bomb gets the green light.

The project to build the uranium bomb is handed to the Army Corps of Engineers, Manhattan District, so, it soon becomes known simply as the Manhattan Project.

And it's top secret.

The project to build the uranium bomb doesn't exist.

In charge of the physics for the Manhattan Project is Robert Oppenheimer, the teenaged boy who'd visited Joachimsthal 20 years earlier.

He's now 38 years old, a chain-smoking, nervous, theoretical physicist with a passion for martinis, women, and ancient Hindu poetry.

A secret city called Los Alamos is built in the remote New Mexico desert.

Oppenheimer's job is to take a rock and build a bomb.

-The automatic control's got it now.

Rob, this time, the stakes are really high.

-The Manhattan Project was the beginning of big science.

Every talented physicist was recruited to work at Los Alamos, and so you had a cluster of Nobel Laureates there.

in the middle of the New Mexico desert.

Enormous sums of money were spent: $2 billion, which was quite a sum in 1945.

This was industrial application of science on a heretofore unheard-of level.

-♪ I never thought I ♪♪ Los Alamos was, in fact, a secret city.

It was known by a post office box.

If you showed up at the gates, asking questions, you were firmly turned away.

The scientists who were drawn to work there were under strict instructions not to talk about it.

Your job, as a scientist, was to essentially do as ordered, to produce sort of the thunderclap that would end World War II.

MULLER: Before the American bomb is ready, Germany surrenders and the war in Europe is over.

[Foreboding music plays] The victorious allies round up every German physicist they can find, including Otto Hahn, the man who had first split the uranium atom.

So, just how far have they progressed in building their bomb?

Hardly at all.

There is no German uranium bomb.

Leo Szilard, the man who urged the president to build the bomb, now drafts a petition urging him to stop.

-In a stunning transformation worthy of uranium itself, the man who conceived of the bomb becomes the world's first antinuclear activist.

But Leo Szilard is ignored.

The United States is still at war with Japan and their work to construct the uranium bomb continues, against technical problems that have never been seen before.

And the biggest is uranium itself.

Natural uranium mined from the ground is mostly U-238, meaning the nuclei contain 238 protons and neutrons.

Fewer than 1-in-100 is this nucleus, U-235.

It has 3 fewer neutrons and it is the nucleus that can split and trigger other U-235 nuclei to split.

So, what the scientists at the Manhattan Project need to do is gather up enough of this U-235 to create critical mass: an amount that can sustain a runaway chain reaction.

The problem is U-235 is almost identical to U-238, so, scientists exploit the tiny difference in weight -- U-235 is ever so slightly lighter -- in order to create enriched uranium, that is, uranium with a much higher concentration of U-235.

Now, by processing individual atoms on an industrial scale, the scientists manage to create a basketball-size lump of 80% pure U-235.

It's the core of a bomb.

And here it is.

[Foreboding music plays] To determine exactly how much uranium they need, physicists perform dangerous experiments incredibly delicately.

They call it "tickling the dragon's tail."

[Growling] Inside this bomb, the dragon sleeps lightly.

About 3 hours' drive from the secret town of Los Alamos, there's a valley named in Spanish, the... the "Journey of the Dead Man."

[Crickets chirp] There are few places on Earth where you can truly say that the world changed forever.

This is one of them.

It was here, in 1945, that they built a 100-foot, 30-meter-tall, tower.

And they hoisted aloft the bomb they have made.

This was a bomb test called Trinity.

On July 16, 1945, at exactly 5:29:45 in the morning, the dragon roars.

Robert Oppenheimer thought of his beloved Indian poetry.

-I remembered the line from the Hindu scripture, the Bhagavad-Gita.

Vishnu is trying to persuade the Prince that he should do his duty and, to impress him, takes on his multi-armed form and says, "Now I am become Death, the destroyer of worlds."

I suppose we all thought that, one way or another.

-When the bomb goes off, it is so incredibly bright, it's like another rising Sun.

The heat from the bomb fuses the desert sand into this green glass.

It's a mineral which is named in honor of the test, trinitite, the first and only time it's ever been created.

You can still -[Beeping] detect radiation coming away from the trinitite, which is about 30 times the background.

So, it's not dangerous, being here today, but it would've been a different story some 70 years ago.

10 days later, the uranium bomb arrives on a tiny island in the Pacific... where it is loaded into a B-29 named after the pilot's mother.

The Enola Gay's mi ssion starts from Tinian in the Marianas.

The crew has had their final briefing on weather and air sea rescue.

The massive bomb ha s been loaded.

At 2:45 in the morning, Au gust 6, 1945, Colonel Tibbets takes the Enola Gay down the runway, into the air, beginning the 6.5-hour fl ight to Japan.

The morning of August 6, 1945, is beautiful and clear in Hiroshima.

People here see a single, silver aircraft gleaming in the sky.

[Foreboding music plays] It's the Enola Gay.

It releases one bomb and, 600 meters directly overhead here, at exactly 8:15 in the morning, it detonates and uranium changes everything, forever.

[Explosion] A rock forged in an exploding star erupts like nothing has ever erupted.

We took a rock and we forced it to release its power.

We woke the dragon.

People closest to the blast are instantly vaporized in the tremendous heat and they leave their shadows etched on the pavement.

This is what the city of Hiroshima looks like on August 6, 1945.

It's a town laid to waste by uranium.

After the nuclear weapon detonates above the city, it already creates a fireball 300 meters in diameter, you can see, represented by that red sphere.

Those not killed in the initial blast and fire will begin to die in the coming weeks from the radiation.

-[Singing nearby] After the bomb, American authorities insist that the people who survived the blast in Hiroshima are not suffering ill effects due to exposure to radiation.

An Australian, Wilfred Burchett, the first Western journalist into the city, finds something the world has never seen before: people suffering from a horrible illness, which we know today as acute radiation sickness.

as BURCHETT: I write this as a warning to the world.

In Hiroshima, people are still dying, mysteriously and horribly from an unknown something which I can only describe as the atomic plague.

All these phenomena, they told me, were due to the radioactivity released by the atomic bomb's explosion of the uranium atom.

-This sickness is something the world has never seen before.

There were clues to this new sickness back in the ancient land, where ancient stories tell of a great power beneath the earth, and it was here I found something extraordinary.

This painting is really fascinating.

It's an ancient health warning.

It shows the sickness you would contract if you disturbed the stones in this area.

See the swelling on the joints?

And, strangely enough, this land has some of the richest deposits of uranium on Earth.

Today, we know the sickness at Hiroshima was due to the strange energy coming from uranium.

When the bomb went off, zillions of uranium nuclei ripped themselves in half, something that never happens in nature, and that released an incredible amount of energy, a lot of which you could see -- the heat and light and the shockwave -- but it also released energy that you can't see.

It's a form of radiation just like light, but so high-energy that it's invisible to our eyes.

This invisible radiation flashed through people at the speed of light.

Even those not directly affected by the immediate blast have their cells seriously damaged at the molecular level.

This new sickness is acute radiation syndrome.

The uranium bomb would continue to kill, 'til the death toll was more than 100,000 people.

Before Hiroshima, almost no one had heard of uranium, and, now, all of a sudden, it explodes into the consciousness of everyone on Earth.

Soon, miners will come for the uranium beneath this country and the indigenous people fear they will disturb the sleeping reptile and unleash earthquakes and fire.

It's the fire of a new age, the Age of Uranium.

In our next episode, uranium takes us into a new age.

It heals the sick and transforms our lives.

As you can hear, from my Geiger counter, I'm getting close to a radioactive source.

Uranium promises a brilliant future -- Manipulating the fundamental particles of the universe from within the atom.

And it threatens to poison the Earth.

"Uranium: Twisting the Dragon's Tail" is available on DVD.

To order visit shoppbs.org or call 1-800-PLAY-PBS.