Ivy King
Ivy King was the largest fission nuclear weapon to not attempt fusion boosting, yielding 500 kilotons of TNT. It was tested on November 16, 1952, on Enewetak Atoll in the Pacific, by the United States' Truman administration as part of Operation Ivy. Alongside the first multi-megaton thermonuclear test in Ivy Mike, the operation was in response to the nuclear weapons program of the Soviet Union.