Nuclear fission Mexico, which was the scientific hub for research on bomb development and design. Other sites, notably the Berkeley Radiation Laboratory and the Metallurgical Laboratory at the University of Chicago, played important contributing roles. Overall scientific direction of the project was managed by the physicist J. Robert Oppenheimer. In July 1945, the first atomic explosive device, dubbed "Trinity", was detonated in the New Mexico desert. It was fueled by plutonium created at Hanford. In August 1945, two more atomic devices – "Little Boy", a uranium-235 bomb, and "Fat Man", a plutonium bomb – were used against the Japanese cities of Hiroshima
History of nuclear weapons found a rough schematic showing a Nazi nuclear bomb. In March 1945, a German scientific team was directed by the physicist Kurt Diebner to develop a primitive nuclear device in Ohrdruf, Thuringia. Last ditch research was conducted in an experimental nuclear reactor at Haigerloch. On April 12, after Roosevelt's death, Vice-President Harry S. Truman assumed the presidency. At the time of the unconditional surrender of Germany on May 8, 1945, the Manhattan Project was still months away from producing a working weapon. Because of the difficulties in making a working plutonium bomb, it was decided that there should be a