Little Boy was the first nuclear weapon used in warfare. It exploded approximately 1,800 feet over Hiroshima, Japan, on the morning of August 6, 1945, with a force equal to 13,000 tons of TNT. Immediate deaths were between approximately 70,000 to 130,000.

Little Boy was dropped from a B-29 bomber piloted by U.S. Army Air Force Colonel Paul W. Tibbets. Tibbets had named the plane Enola Gay after his mother the night before the atomic attack.

Fat Man was the second nuclear weapon used in warfare. Dropped on Nagasaki, Japan, on August 9, 1945, Fat Man devastated more than two square miles of the city and caused approximately 45,000 immediate deaths.

Major Charles W. Sweeney piloted the B-29, #77 that dropped Fat Man. After the nuclear mission, #77 was christened Bocks Car after its regular Command Pilot, Fred Bock.

While Little Boy was a uranium gun-type device (the uranium was manufactured at Oak Ridge, Tennessee), Fat Man was a more complicated and powerful plutonium implosion weapon that exploded with a force equal to 20 kilotons of TNT (the plutonium was manufactured at Hanford, near Richland, Washington).

 Aditional History of "Fat Man" and "Little Boy"