Atomic bomb

Atomic bomb (aka atom bomb) was the name given to the first explosive device to derive its destructive power from, as defined by the Oxford English Dictionary, "the rapid release of energy by fission of heavy atomic nuclei".

Three atomic bombs were detonated by the United States during World War II. The first was a test explosion at Alamogordo, New Mexico, on 16 July 1945. That was the culmination of the Manhattan Project. The bomb was then deployed by the United States Air Force in a bid to end the Pacific War against Japan without the need for an invasion of the Japanese mainland. On 6 August, a bomb codenamed Little Boy was dropped on Hiroshima. There was a second strike against Nagasaki three days later and Japan surrended on 14 August.