On November 1, 1952, the United States conducted the Ivy Mike test, the first full-scale detonation of a thermonuclear, or hydrogen, bomb. The device was exploded at Enewetak Atoll in the Marshall Islands as part of Operation Ivy. It used a large cryogenic deuterium system and was far too bulky to serve as a deliverable weapon, but it proved the Teller–Ulam design for staged fusion. The blast produced a yield of about 10.4 megatons, many times larger than the bombs dropped in World War II. The explosion vaporized the test island and left a huge underwater crater. Ivy Mike marked the beginning of a new phase in the nuclear arms race and influenced U.S. strategic planning during the Cold War.
