McDonald Ranch House , also known as Trinity Site , in the Oscura Mountains of Socorro County , New Mexico , was the location of assembly of the world 's first nuclear weapon . The active components of the Trinity test " gadget " , a plutonium Fat Man-type bomb similar to that later dropped on Nagasaki , Japan , were assembled there on July 13 , 1945 . The completed bomb was winched up the test tower the following day and detonated on July 16 , 1945 as the Trinity nuclear test
Trinity nuclear test
Trinity (nuclear test)
McDonald Ranch House