Shortly after 8:15 am. 6th August 1945. Looking down on the rising smoke from the atomic explosion above the city of Hiroshima from an U.S. Air Force bomber from the 509th Composite Group. By the time this photo was taken; the flash of light and intense heat from a fireball 370 m (1;200 ft) diameter had already taken place; and an intense shockwave radiating out faster than the speed of sound was dissipating; having done most of its damage to ground structures and people in a circle 3.2 km (2 mi) in diameter. Hiroshima; Japan.