The Cuban Missile Crisis was a 13-day confrontation in October 1962 between the Soviet Union and Cuba on one side and the United States on the other side. It was one of the major confrontations of the Cold War, and is generally regarded as the moment in which the Cold War came closest to turning into a nuclear conflict. It is also the first documented instance of the threat of mutual assured destruction (MAD) being discussed as a determining factor in a major international arms agreement. It is the main plot of X-Men: First Class. Sebastian Shaw started it by placing the missiles from Turkey to Cuba.