Little Boy was the code name for the gun-type fission weapon developed by the Manhattan Project. It is historically significant as the first nuclear weapon used in warfare, deployed against the city of Hiroshima on August 6, 1945.
Carried by the Boeing B-29 Superfortress named Enola Gay, the bomb utilized uranium-235 to trigger its explosive reaction. The detonation released approximately 15 kilotons of TNT (63 TJ) of energy, causing an explosion radius of roughly 0.81 miles (1.3 km) and resulting in widespread destruction and loss of life.