Nuclear fission the Manhattan Project during World War II (September 1, 1939 – September 2, 1945) carried out most of the early scientific work on fission chain reactions, culminating in the three events involving fission bombs that occurred during the war. The first fission bomb, codenamed "The Gadget", was detonated during the Trinity Test in the desert of New Mexico on July 16, 1945. Two other fission bombs, codenamed "Little Boy" and "Fat Man", were used in combat against the Japanese cities of Hiroshima and Nagasaki in on August 6 and 9, 1945 respectively. Even the first fission bombs were thousands of
Nuclear arms race until the mid-1950s, the first Soviet bomb was detonated on August 29, 1949, shocking the entire world. The bomb, named "First Lightning" by the West, was more or less a copy of "Fat Man", one of the bombs the United States had dropped on Japan in 1945. Both governments spent massive amounts to increase the quality and quantity of their nuclear arsenals. Both nations quickly began the development of a hydrogen bomb and the United States detonated the first hydrogen bomb on November 1, 1952, on Enewetak, an atoll in the Pacific Ocean. Code-named "Ivy Mike", the project was led