Trinity was the first nuclear weapon detonation, conducted by the United States Army on July 16, 1945, in the Jornada del Muerto desert of central New Mexico as a crucial test of the Manhattan Project’s implosion-type plutonium bomb. Developed after reactor-bred plutonium made a simpler gun-type design unreliable, the device used explosive charges to compress a plutonium core. Kenneth Bainbridge oversaw the test, with J. Robert Oppenheimer directing the laboratory that built the bomb. The explosion proved the design later used for Fat Man, released about 25 kilotons of force, spread radioactive fallout, and marked the practical beginning of the nuclear age.