Since 1945, the world has been living under the shadow of the atomic bomb. Although atomic fission was discovered in 1938, and several nations had undertaken efforts to produce an atomic bomb during World War II, it was only with the destruction of Hiroshima that nuclear weapons burst, fully formed, onto the world stage. Introduced in combat at a time when the world system was being reshaped, nuclear weapons and nuclear power have occupied a privileged place in modern history and culture. This elective explores episodes in nuclear world history, including the international development of nuclear weapons, the arms race, fallout, and nuclear culture.