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 test as a "peaceful nuclear explosion", but according to independent sources, it was actually part of an accelerated covert nuclear program of India. This test generated great concern and doubts in Pakistan, with fear it would be at the mercy of its long–time arch rival. Pakistan had its own covert atomic bomb projects in 1972 which extended over many years since the first Indian weapon was detonated. After the 1974 test, Pakistan's atomic bomb program picked up a great speed and accelerated its atomic project to successfully build its own atomic weapons program. In the last few decades of the