On October 16, 1962, the Cuban Missile Crisis began, the nadir of the Cold War with the closest the world has ever come to World War III.
The Crisis ended on October 28th with the blockade ending on November 20th, 1962....it is generally regarded as the moment in which the Cold War came closest to turning into a nuclear conflict, or possibly World War III, with an American research center estimating that 100 million Americans and over 100 million Soviets would have perished.
The Cuban Missile Crisis