|In late August, 1962, American spy planes detected the building of missile sights in Cuba. Initially the government believed that these sites were defensive in nature. In fact, the Soviets, under Khrushchev, had decided to redress the strategic gap between the two world powers in one quick swoop by placing missiles in Cuba, thus providing the US with a very limited warning if attacked.
On October 15th, US intelligence brought the President conclusive proof that the Soviets were installing medium-range ballistic missiles in Cuba. After much discussion with his advisors, Kennedy ruled out an early air-strike as too risky, and instead decided on a blockade of Cuba.
On the evening of October 22nd President Kennedy addressed the nation, announcing the discovery of missiles in Cuba and the imposition of a blockade on all Soviet ships attempting to deliver weapons to Cuba. The US made it clear that it would fire on Soviet ships which did not observe the "quarantine."
Many felt that nuclear war was imminent. Suddenly, those Soviet ships en route to Cuba reversed course.
The affair was officially resolved when the United States agreed not to invade Cuba, and the Soviets agreed to withdraw their forces and missiles from Cuba. The event was a serious setback for the Soviets. Their strategic weakness forced them to withdraw from what had been a very risky venture.