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
1947–50 in the Vietnam War and foreign affairs. The Accord was denounced by Ho Chi Minh and generated little support in Vietnam. Bảo Đại returned to Vietnam as Head of State after the agreement was formally approved by the French parliament. At a Department of State conference, Consul General George M. Abbott said that the only alternatives to a Bảo Đại government were a colonial war or a communist-dominated government of Vietnam. The Soviet Union detonated a nuclear bomb at a test site, breaking the United States' monopoly on nuclear weapons. The Soviet nuclear test amplified fears by the U.S. and its allies that the