Little Boy " was the codename for the type of atomic bomb dropped on the Japanese city of Hiroshima on 6 August 1945 during World War II . It was the first nuclear weapon used in warfare . The bomb was dropped by the Boeing B-29 Superfortress '' Enola Gay '' piloted by Colonel Paul W. Tibbets , Jr. , commander of the 509th Composite Group of the United States Army Air Forces . It exploded with an energy of approximately and caused widespread death and destruction throughout the city . The Hiroshima bombing was the second man-made nuclear explosion in history , after the Trinity test , and the first uranium-based detonation
Trinity test
Trinity (nuclear test)
Little Boy