Hiroshima was targeted by the atomic bomb named Little Boy on 6 August 1945. The bomb was carried by the B-29 bomber Enola Gay and detonated over the city during the final weeks of World War II.
Little Boy was a gun-type nuclear weapon using highly enriched uranium. It was developed by the Manhattan Project and had a yield of approximately 15 kilotons of TNT, although estimates vary by source and method.
The aircraft dropped the bomb at about 8:15 a.m. Japan Standard Time. Hiroshima was selected because it was a large urban and military-industrial center and had not been heavily damaged by earlier bombing, allowing the effects of the new weapon to be assessed.
Three days later, the United States dropped Fat Man on Nagasaki. The two attacks were the first and only wartime uses of nuclear weapons, and Japan announced its acceptance of surrender terms on 15 August.