The Cold War began after World War II between the Soviet Union and the United States and lasted from 1947 to 1991. It was an ideological conflict between capitalism and communism that did not involve direct military combat. Key figures included Joseph Stalin of the Soviet Union, John F. Kennedy and Harry S. Truman of the United States. Major events during the Cold War included the Soviet development of nuclear weapons, the formation of NATO and the Warsaw Pact, and the Cuban Missile Crisis. The Cold War ended in 1991 with the fall of the Soviet Union.