Hiroshima was targeted by the Little Boy atomic bomb on August 6, 1945.
Little Boy was a uranium-235 gun-type fission weapon developed by the Manhattan Project. A B-29 bomber named Enola Gay dropped it over Hiroshima, where it detonated during the final weeks of World War II. The bombing caused enormous destruction and loss of life, most of it among civilians.
The target is sometimes confused with Nagasaki, which was bombed three days later by a different weapon called Fat Man. Hiroshima and Nagasaki were the first and only cities to experience nuclear attacks during an armed conflict.
The bombings occurred after the Allies issued the Potsdam Declaration demanding Japan’s surrender. Japan announced its acceptance of the declaration on August 15, after the Hiroshima bombing, the Nagasaki bombing, and the Soviet declaration of war. The formal surrender document was signed on September 2 aboard USS Missouri.