The first nuclear device was detonated as a test by the United States at the Trinity site on July 16 , 1945 , with a yield approximately equivalent to 20 kilotons of TNT . The first thermonuclear weapon technology test of an engineered device , codenamed " Ivy Mike " , was tested at the Enewetak Atoll in the Marshall Islands on November 1 , 1952 ( local date ) , also by the United States . The largest nuclear weapon ever tested was the " Tsar Bomba " of the Soviet Union at Novaya Zemlya on October 30 , 1961 , with the largest yield ever seen , an estimated 50 – 58 megatons
Ivy Mike
Ivy Mike
Nuclear weapons testing