The Manhattan Project | Secret Cities | 2
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Imagine it's April 15th, 1943, in the mountains 25 miles northwest of Santa Fe, New Mexico. You're a scientist specializing in the purification and production of metallic substances. The late afternoon sun casts a golden glow on the mountains in the distance, but it's hard to appreciate the natural beauty when construction crews are hammering at such a frantic pace all around you.

You've been recruited to move here and take part in a top-secret project. All you've been told is that it will help the United States win the war. Today, though, you've been summoned to a meeting where hopefully you'll learn more. You turn the corner and climb up the front steps of a three-story timber building. As you step through the front door, greeting the meeting attendees is someone you recognize. Dr. Serber, is that you? No.

Robert Serber is the physicist who recruited you for this assignment. He's tall and thin, wearing glasses. He looks to be in his 30s. He reaches out to shake your hand. How's your family liking your new home? Well, it's certainly cozy. Might be tricky to give our two-year-old a bath when we don't have a tub. But I'm sure we'll figure something out. Dr. Serber, though, may I ask, where is my laboratory going to be? That's a fair question. When they finish building it, it'll be about half-mile south of here in the technical area.

Till then, we'll set up a space for you right up those stairs. And what is this building? This is the old Los Alamos Ranch School. It was a school for boys until we bought it a few months ago. But now it'll be our base of operations until they can get caught up with construction. Dr. Serber looks down at his watch. We need to get started. All right, follow me. I'll show you to the library.

You struggle to keep up with Dr. Serber as he dashes down the hallway. "But Dr. Serber, are we going to learn more about what we're actually here to do?" "Oh, you will. And I think you'll understand why we've been holding that information so close to the chest." As you follow Dr. Serber into the library, you see about 30 other people seated in folding chairs, waiting for the meeting to start. Many of them look as confused and disoriented as you feel.

As you take your seat, you notice a thin man wearing a flat-brimmed hat standing in the corner. You recognize him immediately as J. Robert Oppenheimer, the man in charge of the project. After a few moments, Dr. Serber steps to the center of the room to address the group. Well, good afternoon, and thanks for joining us. For those who don't know me, I'm Robert Serber. Dr. Oppenheimer and I are here today to brief you on what we're all here to do.

Serber nervously removes a stack of index cards from his coat pocket and stares down at them. Now, the object of this project is to produce a practical military weapon in the form of a bomb, in which the energy is released by a fast neutron chain reaction in one or more of the materials known to show nuclear fission. Your mind races as you process what you're hearing.

Now all the secrecy makes sense. In 1939, the world learned it was possible to split an atom. Ever since, you've debated with your colleagues over how that knowledge could lead to the creation of a bomb of unimaginable power. Now you realize that by agreeing to come to this remote and rustic setting, not only could you help win the war, you could help open the door to a new future for humanity.

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From Wondery, I'm Lindsey Graham, and this is American History Tellers. Our history, your story. American History Tellers

In the summer of 1942, President Franklin Delano Roosevelt ordered the creation of a military endeavor tasked with building the first atomic bomb. It was called the Manhattan Project. Its leaders were General Leslie Groves of the Army Corps of Engineers and a 38-year-old theoretical physicist named J. Robert Oppenheimer. Their mission was to build the bomb before Hitler's Germany could, but they faced daunting challenges.

In November of 1942, Groves and Oppenheimer selected a remote mesa in the mountains outside Santa Fe as the site for a new development called Los Alamos. Hidden there behind barbed wire would be state-of-the-art laboratories and facilities devoted to one purpose, designing and building the first atomic bomb.

Meanwhile, the uranium and plutonium needed for the bomb was being produced in sprawling new developments in Tennessee and Washington state. And as the operations of the Manhattan Project continued to grow, U.S. military leaders struggled to keep its top-secret work hidden from enemies and rivals. This is Episode 2 of our three-part series on the Manhattan Project, Secret Cities.

In March 1943, J. Robert Oppenheimer, his wife Kitty, and their one-year-old son Peter moved into a two-bedroom log and stone house near the Los Alamos Ranch School in northern New Mexico. The site had been selected just four months before, and already nearly 100 scientists, engineers, and support staff called the mesa home.

But many more were soon to arrive. By the end of 1943, thousands of civilian and military personnel would be needed at Los Alamos to keep the project going. Construction continued at a frantic pace to be ready for them. Facilities were planned to spread out over an area that spanned more than 28,000 acres. The Los Alamos Ranch School was in the northern section of the site, which became known as the town, where houses, apartments, barracks, and dormitories were constructed.

And residents in the town wasn't limited to those working on the Manhattan Project. Many of the scientists and technicians brought their families with them. And eventually, Los Alamos would be home to schools, general stores, and recreational facilities to serve the new community.

South of the town, hidden behind a 10-foot-tall barbed wire fence and monitored by armed guards and towers, was a restricted compound called the Technical Area. This sprawling complex of 37 buildings, including laboratories, warehouses, shops, and administrative buildings, was where the actual work of designing the bomb would take place. And access to this area was limited to scientists and military personnel with appropriate security clearance.

In order to achieve the construction of such a vast complex, everything at Los Alamos was designed to be built quickly and cheaply. So when the scientists arrived, many were shocked by the crude conditions, the shoddy construction, and the profound sense of isolation. But it didn't take long for them to become fully absorbed in the monumental task they were charged with.

Four months earlier, in December of 1942, a team of scientists led by Italian physicist Enrico Fermi had triggered the first controlled atomic chain reaction at the University of Chicago. Because of Fermi's groundbreaking experiment, scientists at Los Alamos knew it was possible to release energy from a large number of atoms in a short period of time.

Oppenheimer and his team were now tasked with creating an infinitely faster and more powerful chain reaction than Fermi's nuclear reactor. What's more, they needed to figure out how to do it inside the tight confines of a bombshell.

Prior to the launch of the Manhattan Project, Oppenheimer had led a small team of physicists in devising theories for how this might be done. He knew that scientists arriving at Los Alamos would need to be educated on that work in a clear and concise way. Oppenheimer delegated that assignment to a former student of his, 34-year-old physicist Robert Serber.

Serber developed a series of lectures, which were adapted into a booklet known as the Los Alamos Primer. In it, Serber spelled out the two leading theories for how an atomic bomb might be built.

The first was the gun method. Two pieces of uranium or plutonium would be positioned inside a cylindrical bombshell at opposite ends. To detonate the bomb, explosive material packed inside one end of the shell would shoot one of the pieces of uranium or plutonium at high velocity like a gunshot, slamming it into the other piece.

The impact would create a single, hyper-dense piece of uranium or plutonium, dense enough that a high-speed chain reaction would occur, splitting trillions of atoms in a fraction of a second. The result would be a massive explosion.

The second theory involved creating a sphere of uranium or plutonium about the size of an orange and encasing it in a shell of traditional explosives. When those explosives were set off, the force would violently compress the fissionable material inside, reaching the necessary density to go critical, the state which triggers a rapid chain reaction. This process was called the implosion method.

Serber laid out the myriad of challenges involved in both designs. The gun method ran a risk of starting the chain reaction prematurely, and the implosion method had to be perfectly calibrated, applying equal pressure from all sides to the material inside, and the team had to figure out how to mold the uranium and plutonium into the highly customized shapes that would work properly with the mechanics of the weapons.

Oppenheimer divided the scientists into four separate teams that were focused on solving these problems. The theoretical physicists developed the mathematical calculations to predict the best strategies for executing both the gun and implosion methods. Experimental physicists worked on putting those theories to the tests. Chemists were tasked with developing the metals required by the weapon. And lastly, a team of ordnance experts devised the highly specialized explosives that would trigger the chain reactions.

But as the months passed, Oppenheimer encountered another obstacle. The Manhattan Project was a military mission, under the supervision of General Leslie Groves. And Groves was determined to do everything in his power to keep the work secret.

Groves understood that the less the scientists knew about the overall design of the bomb, the less a chance there would be for key information to be leaked. So the general demanded that the scientists' work be compartmentalized. Scientists were only given the information they needed to accomplish their assigned task without knowing how that work fit into the bigger picture of the Manhattan Project.

And at first, Oppenheimer did his best to follow Grove's directive, but over time, he and his core team found the policy to be impractical. In their view, it flew directly in the face of the scientific method, which valued openness and peer review. So against Grove's wishes, every Tuesday evening, Oppenheimer called a general meeting, where dozens of the leading scientists at Los Alamos collaborated, shared ideas, and solved problems together.

In Oppenheimer's view, the information shared was critical to maintaining a rapid pace of development. This free-flowing communication frustrated Groves, but he knew he had to trust the expertise of the scientists. Still, his security team continued to clamp down on any potential leaks. If they couldn't keep the scientists from talking to each other, perhaps they could focus their efforts on keeping the scientists from talking to anyone else.

Groves wasn't concerned that the residents of Los Alamos would transmit information to German or Japanese authorities. He was confident that all the scientists were united by their disdain for Hitler and the other Axis allies. But Groves' security advisors had identified another threat.

Most of the scientists at Los Alamos were politically left-leaning. In the wake of the Great Depression, academic communities were, by and large, supportive of initiatives like the New Deal, which aimed to close the gap between the wealthy and the working class. And some had gone so far as to become members of the Communist Party of the United States, which they saw as an advocate for the labor movement. Many who weren't communists themselves had close friends or associates who were.

And in 1943, it was perfectly legal to be a communist in the United States. But the security officials keeping watch over the Manhattan Project knew that communists and their friends might make key information available to agents of the Soviet Union. Although the Soviets were allies of the United States in the fight against Hitler, the U.S. government also saw them as rivals, fearing that if Russian power wasn't kept in check, the Soviets' influence in the post-war world would create challenges for America.

General Groves knew it was a top priority to keep the discoveries of the Manhattan Project secret from the Soviets. And it didn't take long for counterintelligence officials to identify one key resident of Los Alamos as a security risk. Imagine it's June 1943 in Washington, D.C. You work in military intelligence, and you've just stepped inside an office in a government building in the Capitol.

A stout man behind a large desk invites you to take a seat. It's General Leslie Groves. You're one of the leading security officials who report to him, and today it's your job to deliver information related to the security of the Manhattan Project, information you find alarming. Good morning, sir. Thank you for taking the time. Colonel, please, let's get on with it.

You know that General Groves is a busy man, and he's known for being blunt. So you don't waste any time. Well, General, you may be aware that several days ago, J. Robert Oppenheimer traveled to San Francisco. I'm aware he was set to meet with Ernest Lawrence and the team at Berkeley Radiation Lab. That's correct. Due to Dr. Oppenheimer's past associations with members of the Communist Party, we assigned two counterintelligence core agents to track his movements. Oh, did you now?

and pass a manila folder to General Groves. You'll see from these photos that our agent spotted Oppenheimer meeting with his former lover for dinner, a 29-year-old psychiatrist named Gene Tatlock. And that's a problem? Well, after dinner, they rode together in a car to Miss Tatlock's apartment. The two of them were not seen again until they emerged from the apartment building at 8.30 the following morning.

Groves raises his eyebrows. So Oppie's having an affair. Well, I don't approve of that behavior, but it's nothing that we... Sir Jean Tatlock is a known member of the Communist Party, and as such, we must assume that she's sympathetic to the communist regime of the Soviet Union. If she were made privy to the work underway at Los Alamos or Oak Ridge or Hanford, there's a clear danger she could pass that information directly to Soviet agents. Groves looks you in the eye for a moment, and he opens the envelope and inspects the photos inside.

You take a deep breath, working up the nerve to give Groves your assessment. So, sir, it is my belief that Dr. Oppenheimer should be removed from the Manhattan Project. You have direct evidence that J. Robert Oppenheimer shared secrets with Miss Tatlock? You clench your teeth. No, sir, we do not. Well, I do not condone Dr. Oppenheimer's reckless behavior, and I will speak to him on that matter. But having said that, Colonel, I am sure you can appreciate the fact that we are embroiled in a race to build an atomic bomb before Hitler does.

General Groves hands the envelope back to you. Changing leadership at this point in the process will waste valuable time. Time we simply do not have. Do I make myself clear? Yes, sir. All right then. Thank you, Colonel. You're excused. You nod quietly and leave, clenching your fists as you walk down the hallway. You've dedicated your career to defending the United States from the scourge of communism. The Soviet Union may be an ally now, but as long as communists are in power there, as far as you're concerned, they're the enemy as well.

So you're furious that Groves is playing fast and loose with some of the nation's most precious secrets. You vow to keep a close eye on Oppenheimer. Brilliant or not, he's a risk to the security of the United States.

Colonel Boris Pash was born in the United States, but his father was a citizen of Russia. Pash moved to Russia when he was 12 years old and stayed for eight years. While there, he witnessed the Bolshevik Revolution firsthand and saw the violence that followed. As one of the senior intelligence officers assigned to the Manhattan Project, Pash saw communism as an existential threat to the United States.

General Groves understood this and was privately alarmed when Pash voiced his concerns about Oppenheimer's rendezvous with Gene Tetlock. But as Groves weighed his options, he knew the best path forward was to keep Oppenheimer in charge at Los Alamos.

But still, Groves shared Pash's concerns about communism, and he knew that many working at Los Alamos had communist friends. There was much about the culture and behavior of the scientists that Groves didn't understand or approve of, but what he did know is that for the Manhattan Project to be successful, he needed their expertise.

But the incident with Tatlock wasn't the only time that Oppenheimer's behavior alarmed security officials. Groves and his intelligence officers kept Oppenheimer and other scientists under close surveillance, but they had already missed a significant breach. Sources inside the Manhattan Project were already feeding information to Soviet spies, and some of those sources would soon gain access to Los Alamos' most secret breakthroughs.

By December of 1943, scientists at Los Alamos had been feverishly working for 10 months. The complex and the hills of northern New Mexico had grown to house more than 3,000 scientists, military personnel, and civilians. As the physical experiments and prototyping grew more elaborate, J. Robert Oppenheimer knew that the population would have to grow to keep pace.

All this activity was a problem. Twenty-five miles south in Santa Fe, rumors swirled about the mysterious compound up at the mesa. Some thought that a powerful new submarine was being constructed. Others thought that perhaps a nudist colony had been established there. But somehow, the secret project remained hidden.

And within this veil of secrecy, Oppenheimer's team continued exploring the parallel paths of both the gun approach and the implosion design. But by the end of 1943, Oppenheimer's estimates for how much plutonium or uranium would be required by those designs rose dramatically. General Groves ordered the plants in Oak Ridge to expand so production could increase too.

In the meantime, Groves and Oppenheimer were still in the dark about what was happening in Germany. For all they knew, Hitler's team of scientists already had a viable design figured out, but Oppenheimer soon welcomed a visitor to Los Alamos who would shed valuable light on what was happening across the Atlantic.

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On December 30, 1943, Nobel Prize-winning physicist Niels Bohr arrived at Los Alamos. Bohr lived and worked in Copenhagen, Denmark, which had been under German occupation since 1940. Bohr was also of Jewish descent, and earlier in 1943, he received news that the Nazis were preparing to arrest him. Soon after, Bohr escaped to England.

The 58-year-old Bohr was a hero to the scientists gathered at Los Alamos, including Oppenheimer. In the late 1920s, Bohr had been a pioneer in helping the world understand how atoms were structured. Indeed, many of his theories were foundational to the work that was currently underway at Los Alamos. But even still, at a private meeting with Oppenheimer and his core team of scientists, Bohr was surprised to hear of the rapid progress that had been made in the development of the bomb.

But Bohr had some news of his own to share. In September of 1941, he had held a meeting with his former student, now the most famous physicist in Germany, Werner Heisenberg. The scientists at Los Alamos had all rightly assumed that if a German project to develop an atomic bomb was underway, Heisenberg would lead it.

And in his meeting, Bohr not only confirmed that the Germans had been exploring the possibility of a bomb, he produced a rough sketch of how Heisenberg was imagining it would work. But when Oppenheimer and his team reviewed the sketch, they breathed a huge sigh of relief. Heisenberg's device might produce an atomic chain reaction, but the explosion wouldn't be much larger than what could be produced by conventional explosives like TNT.

Oppenheimer now knew that the Los Alamos team was much more advanced in their understanding of how an atomic bomb could actually work. But Bohr had another reason for visiting Los Alamos. He understood that the development of the weapon was inevitable and necessary to win the war. Still, Bohr had a vision of the dangers that might materialize after World War II came to an end.

If the Soviet Union were caught by surprise that Western countries had successfully developed a weapon of this power, Bohr believed that they would be forced to develop an atomic arsenal of their own. Bohr knew the Soviets had the expertise and the resources to pull it off. A nuclear arms race would ignite, one that would not only jeopardize national security, but threaten the planet itself.

But Bohr also believed there was a solution. He envisioned a world where breakthroughs like atomic energy would be openly shared across international lines for the betterment of all. To that end, Bohr believed that the Soviets should be made aware of the Manhattan Project before the bomb was a reality.

Bohr shared these concerns and vision with Oppenheimer and his core team. His ideas resonated with many of the scientists at Los Alamos. Everyone had been so embroiled in the complexity of what they were tasked with, they hadn't had the time to step back to envision the long-term consequences of what they were doing. But despite being sympathetic to Bohr's perspective, Oppenheimer chose not to advocate for him, believing the country's political leaders were better qualified to make such decisions.

Oppenheimer also wanted to keep his job. He knew that because of his interactions with known communists, he was already under surveillance. He wanted to steer clear of any other behavior that could raise suspicion among security officials.

So the following year, Bohr took his case directly to President Franklin Roosevelt and British Prime Minister Winston Churchill, urging for a policy of openness to be embraced with the Soviets. Roosevelt and Churchill were unmoved. Not only did they continue to hide the Manhattan Project from the Soviets, they ordered that Bohr's activities be tracked by intelligence officials for fear he might share secrets with the Russians himself.

But Bohr's report about his meeting with Heisenberg gave General Groves confidence that the Manhattan Project stood a good chance of outpacing the Germans. And then, in the spring of 1944, he got even more good news. Intelligence suggested that the Germans were stumbling in their attempts to develop a bomb. But despite having the advantage, Groves and Oppenheimer continued to drive their teams forward at a breakneck pace.

The scientists at Los Alamos were making progress on the design of the bomb, but none of that would matter if they didn't have enough uranium or plutonium to power the explosion. And in Oak Ridge, Tennessee, work was well underway to meet that need. Imagine it's the summer of 1944, in a factory in Oak Ridge, Tennessee. A few weeks ago, you started work here as a machine operator. And it's the strangest job you've ever had.

You're sitting on a stool in front of a console that's filled with dials and gauges. A long row of fluorescent lights flickers above you, illuminating the hall where 20 other women sit in front of consoles identical to yours.

Your manager is peering over your shoulder, checking the dials on your console. Looking good. You've gotten the hang of this. Thanks. The needle over here is the one that seems to be moving the most, so I've been turning this dial to keep it in the zone. That's exactly right. You're doing great. But can I ask, what are these needles measuring? Well, behind this wall, there's a big machine, and those gauges are measuring the activity that's happening in that machine. And what about all these other girls? Same thing. You're all making sure the machine keeps running properly. Okay, but...

"'What is the machine doing? I mean, is it making something?' Bill smiles and then shrugs. "'Your guess is as good as mine. All we need to know is that it's going to help our boys win the war, right?' "'Guess so.' Bill points to your wrist. "'Now that's a lovely watch, but remember your training. Behind this wall are some mighty powerful magnets.' You remove the watch and slide it into your purse. "'Yeah, I forgot. No worries. Just keep up the good work. And no jewelry.'

Bill, there's an emergency, Bill!

Bill runs back into the room and shakes his head. Oh boy, I warned him. Bill, that magnet's going to crush him. We've got to turn off the machine. That's not going to happen. If we turn off the machine, it'll take weeks to get it up and running again. I don't know, Bill. He's really stuck. He's hurting. I know. All right, all right. Wait here. Bill grabs something from the corner of the hallway. The other workers keep fighting to move the steel plate, but it won't budge. All right, all of you, take this two-by-four. See if you can use it to pry him off.

The workers wedge the wood underneath a gap in the plate. Several of them brace their legs against the wall and pull on the 2x4 with all their might. Suddenly, the steel plate falls away from the wall. A pinned worker drops to his knees, fighting to catch his breath. You kneel next to him, seeing if he's okay. Bill motions to the other workers to get their attention. Alright everyone, I am sorry for that distraction, but let that be a reminder that the magnets behind this wall are no joke.

Now, we've all got important work to do here. Let's get back to it. You and the other operators move back to your consoles as the maintenance workers carefully move the steel plate down the hall, stepping gingerly away from the magnet. You may not know what you're doing here exactly, but at least it's not boring.

Less than a year after General Groves selected the site at Oak Ridge, Tennessee, the first uranium production plant was already up and running, and there were 66,000 people living in the secret city working at the plant and other facilities nearby.

The plant at Oak Ridge was dubbed Y-12, and it utilized powerful electromagnets to extract the U-235 that was needed for the bomb from raw uranium. This incredibly complex process was monitored by machines called calutrons, which were designed by Ernest Lawrence, Oppenheimer's colleague at the University of California at Berkeley.

In the early days of Y-12, scientists from the university operated the dials and levers that ensured the calutrons were functioning properly. But by the summer of 1944, those scientists had been replaced by a corps of thousands of young women, most of whom had no more than a high school education. These young women became known as the calutron girls and soon proved more adept at producing U-235 than the scientists who preceded them.

But as successful as the women were at managing their consoles, the production of U-235 remained painfully slow. When Y-12 was functioning normally, it took the plant a week to produce just one or two ounces of U-235. Oppenheimer and Groves estimated that it would be well into 1945 before the plant generated enough material to arm a single bomb.

Luckily, Groves had another plant under construction at Oak Ridge. This one would utilize a chemical process to facilitate the extraction of U-235. And by the time the construction was set to be finished in 1945, it would feature a central building four stories tall and half mile long, making it the largest building in the world. And between 1943 and 1945, the facilities at Oak Ridge grew so expansive, it took roughly one-seventh of the nation's electricity to run them.

But by the spring of 1945, Oak Ridge was sending more U-235 to the scientists at Los Alamos. A plant in Hanford, Washington was also producing more plutonium for the project. Soon, Oppenheimer's team finally had the fuel they needed and was refining the two separate designs for the atomic bomb. Now, pressure was building to put those designs to the test.

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From plumbing to electrical, roof repair to deck upgrades. So leave it to the pros who will get your jobs done well. Hire high-quality certified pros at Angie.com. By the spring of 1945, the laboratory at Los Alamos had tested various components for both the gun and implosion methods, but they had yet to test a fully loaded atomic bomb. Still, J. Robert Oppenheimer and his team were growing more confident that they were close to having two viable designs that could be used to win the war.

The gun approach to the design had turned out to be simple and reliable. The only major problem was that scientists had determined that plutonium would not work in this kind of bomb since there was a high risk its chain reaction could be triggered prematurely. So only uranium-235 would work in the gun design. But the facilities at Oak Ridge were still producing U-235 at an incredibly slow pace. That meant production of future gun-designed bombs would be slow as well.

At the plant in Hanford, Washington, however, production of plutonium was accelerating. And based on their calculations, Oppenheimer and his men believed that plutonium could still be a viable fuel for the implosion version of the design.

So perfecting the implosion design became a higher priority for Oppenheimer and his team. Still, this approach was far more complex. It required a perfectly symmetrical explosion to be triggered in the outer shell of a spherical bomb. If successful, that explosion would violently compress the plutonium core inside without allowing any of the fissionable material to escape. At least, that was the theory.

But Oppenheimer believed it was a theory that required a physical test, and he had been making the case to General Leslie Groves. Initially, though, Groves resisted the idea. Plutonium was far too precious to be wasted on a test, and he was eager to get a bomb into the hands of the military as soon as possible.

But ultimately, Groves knew that if a bomb were dropped over an enemy city, and it turned out to be a dud, the enemy would be able to extract vital secrets from the unexploded weapon. This persuaded him that a test of the bomb was crucial. More importantly, Oppenheimer and his team only had theories about how powerful an atomic explosion would be. The only way they would know for sure was to see it in action.

So in April of 1945, planning for the first atomic test was well underway, even if its actual date remained unknown. Oppenheimer assigned a special code name for the test, Trinity. But then the nation was struck by a series of events that made the scientists at Los Alamos question whether a test was even necessary.

On April 12, 1945, U.S. Vice President Harry Truman was summoned to the White House. There, he was greeted by First Lady Eleanor Roosevelt, who informed Truman that earlier that day, President Franklin Delano Roosevelt had suffered a stroke and died soon after. Within hours, Truman was sworn in as the 33rd President of the United States.

Truman immediately summoned a meeting of the cabinet, where he assured them he had every intention of continuing Roosevelt's policies. After the meeting, one person stayed behind, Secretary of War Harry Stinson. Stinson then informed Truman of the secret operation underway across the country, one to develop a new explosive of unfathomable power. This was the first time Truman had heard anything about the atomic bomb.

Roosevelt had been well-respected among the scientists working at Los Alamos. But now, the powerful weapon they were creating would be put into the hands of a new leader. And before Oppenheimer could get a sense of whether Truman would be as thoughtful as his predecessor, the war in Europe took a remarkable turn. Just two and a half weeks after Roosevelt's death, on April 30th, Adolf Hitler died by suicide. By May 7th, Germany surrendered to Allied forces.

The war that had consumed Europe for over five years was over. But beating the Germans and the race to build the bomb had been the key reason the Manhattan Project was launched. Now, with Germany defeated, many at Los Alamos wondered if the project should continue.

But in early May, Oppenheimer forwarded a memo to his team from the Secretary of War. The development of the bomb was to move forward with all possible speed. It was clear to Oppenheimer that President Truman wanted this powerful new weapon in his arsenal. Because even though the war in Europe was over, the war in the Pacific was still raging. U.S. military leaders were in agreement with their new commander-in-chief.

If an atomic bomb could bring a speedy end to the conflict and save American lives, then they wanted to have that power at their disposal. But the nation's leaders didn't realize that another country was laying the groundwork to develop their atomic weapon. And they already had a clear view of what was happening behind the veil of secrecy at Los Alamos.

Imagine it's June 2nd, 1945, in Santa Fe, New Mexico. The afternoon sun is beating down as you stand on a lonely bridge, scanning the road on either side in both directions. You're supposed to be meeting someone here, someone who possesses valuable information, but they're late. You traveled from Philadelphia for this meeting. It'd be a shame if you came all this way for nothing. But then you see a blue Chevrolet headed in your direction.

You breathe a sigh of relief as it comes to a stop in front of you. You open the door and slide into the front seat. You're late. I know. I'm sorry. I had a flat tire.

You've met the driver before. He looks like he's in his 30s, tall and thin with glasses. A physicist named Klaus Fuchs. And for the last 10 months, he's been working up the hill at Los Alamos. Well, I must say, Dr. Fuchs, you're looking much healthier than the last time I saw you. Oh, thank you. I've been hiking every Sunday since I moved up to the mesa. I think that's done me some good. Fuchs turns a corner and heads toward the edge of town.

Finally, he finds a vacant lot and parks the car. Then he starts giving you what you came for. Well, we're gearing up for a test of the plutonium bomb. Not exactly sure when yet, but it's going to happen soon. Probably next month. Where? He found an isolated spot out in the desert, about 200 miles from here. All right. Can you let us know when you find out a date? I won't be able to do that. No. All communication coming out of Los Alamos is under surveillance. Phone calls, letters, everything.

Hmm, alright. You got it. What is it? Hmm.

You open the envelope and thumb through the diagrams and equations. For the past five years, you've been moonlighting as a courier, delivering secrets to the Soviet Union. And this delivery is going to top them all. Harry Gold was an American citizen and chemist who secretly worked as an agent for the Soviet Union. In June of 1945, Gold traveled to New Mexico for a secret meeting with Klaus Fuchs, a physicist who was living and working behind the gates of Los Alamos.

A member of the Communist Party, Fuchs had fled Germany in the 1930s and despised both Hitler and Nazism. He had been part of the British atomic research team since 1941. But after understanding that the research could culminate in the creation of an atomic weapon,

Fuchs immediately became concerned. He worried that too much power would be placed in the hands of Western countries, and he could foresee a time after the war when those countries wouldn't hesitate to use that power against the Soviet Union.

So not long after joining the project, Fuchs reached out to communist colleagues in Great Britain who opened a line of communication to the Soviets. He had been relaying vital information about the atomic bomb ever since. Fuchs' betrayal was purely ideological. At no point did he accept any payment for his services.

But what Fuchs didn't realize is he was just one of four people inside the Manhattan Project who was feeding secrets to Soviet spies. Once this war ended, America would still face a new enemy, one that now had the information and resources to develop an atomic bomb of their own.

Following the defeat of Germany, President Harry Truman, Prime Minister Winston Churchill, and Soviet Premier Joseph Stalin released a joint announcement to the world. Beginning on July 17, 1945, the three leaders would meet in Potsdam, Germany, to negotiate post-war planning. This would be Truman's first meeting with Stalin. The new president wanted to project strength and understood that in the post-war world, the U.S. and USSR would be rivals.

So at the end of June, General Groves communicated a directive to Oppenheimer. The first test of an atomic bomb had to take place no later than July 16th, the day before the meeting in Potsdam. Oppenheimer pushed back, hoping to gain a few more days, but Groves wouldn't budge. The countdown to the Trinity test had begun. From Wondery, this is Episode 2 of the Manhattan Project for American History Tellers.

On our next episode, J. Robert Oppenheimer and the Los Alamos team race to perform the first physical test of an atomic bomb. If successful, humanity will enter a bold new age. But the scientists of the Manhattan Project struggle with a cold reality. Their powerful new creation may be unleashed on innocent civilians.

If you'd like to learn more about the Manhattan Project, we recommend American Prometheus by Ky Bird and Martin J. Sherwood, and Bomb! The Race to Build and Steal the World's Most Dangerous Weapon by Steve Shankin.

American History Tellers is hosted, edited, and produced by me, Lindsey Graham for Airship. Audio editing by Christian Paraga. Sound design by Molly Bach. Music by Lindsey Graham. This episode is written by Matt Almos, edited by Dorian Marina, produced by Alita Rozanski. Our production coordinator is Desi Blaylock. Managing producer, Matt Gant. Senior managing producer, Ryan Lohr. And senior producer, Andy Herman. Executive producers are Jenny Lauer-Beckman and Marshall Louis for Wondery.

Hey, I'm Mike Corey, the host of Wondery's podcast, Against the Odds. In each episode, we share thrilling true stories of survival, putting you in the shoes of the people who live to tell the tale. In our next season, it's July 6th, 1988, and workers are settling into the night shift aboard Piper Alpha, the world's largest offshore oil rig.

Home to 226 men, the rig is stationed in the stormy North Sea off the coast of Scotland. At around 10 p.m., workers accidentally trigger a gas leak that leads to an explosion and a fire. As they wait to be rescued, the workers soon realize that Piper Alpha has transformed into a death trap. Follow Against the Odds wherever you get your podcasts. You can listen ad-free on Amazon Music or the Wondery app.