Germany’s nuclear fusion discovery was overshadowed by the departure of many top physicists, who were Jewish and left due to increasing anti-Semitic views fueled by Nazi propaganda. Those who fled to the United States brought with them the alarming news that the Nazis were developing an atomic bomb. In response, the Pentagon launched its own top-secret operation, the Manhattan Project.
Allied secret agents were dispatched to Germany on the Alsos Mission to sabotage the Nazi atomic program, with targets including the program’s headquarters, hoarded uranium, and Werner Heisenberg, believed to be leading the project. Intelligence led the agents to the town of Haigerloch, where Heisenberg was rumored to be. Upon arrival, they discovered a suspicious-looking cave beneath the town’s castle, where they found a nuclear reactor but no uranium. After three days of interrogation, the physicists finally revealed the location of the buried uranium, which was sent to Britain.
Heisenberg was eventually captured on May 3, 1945, and taken to Britain for questioning, just four days before Germany’s surrender. During this time, more than a thousand tons of Nazi uranium were shipped to the United States for the Manhattan Project. Heisenberg and nine other German physicists were held in a country house in England but were uncooperative. However, hidden microphones around the house eventually captured their conversation on August 6, 1945, when they learned that the USA had dropped an atom bomb on Japan. The physicists tried to figure out how the Americans had done it, revealing that Heisenberg had miscalculated nuclear physics in his design for an atom bomb, which required thousands of kilograms of uranium, while the Hiroshima bomb used just fifty-six kilograms.
After the war, Heisenberg was released as he was no longer considered a threat, and he returned to Germany.