As Japan marked the 69th anniversary of the atomic bombing of Hiroshima on Wednesday, the scars of the atomic bombing will never be forgotten An American B-29 bomber named Enola Gay dropped an atomic bomb on Hiroshima on August 6, 1945, in one of the final chapters of World War II. It had killed an estimated 140,000 by December that year. The newly discovered photograph shows the infamous Hiroshima atomic bomb mushroom cloud still floating above Japan half an hour later.The picture was taken immediately after the bomb was dropped on Japan on August 6, 1945, and shows the cloud parting in to two separate sections.