This basically summarises what it was all about. It is intended to be background information to understand how the Cuban Missile Crisis started, what happened and how it ended.
After Fidel Castro seized power in 1959, he openly declared his Communist affiliations and invited aid from the Soviet Union (since the U.S. had already stopped trading with Cuba). Over the next few years, the U.S. actively attempted to get rid of Castro, most notably in the failed Bay of Pigs invasion in 1961 (in which a poorly trained force of Cuban immigrants was quickly defeated by Castro’s soldiers).
The U.S. had already deployed nuclear missiles very close to the U.S.S.R.’s borders. Although they weren’t nearly as close to major Russian cities as the Cuban missiles were to Miami, the missiles the U.S. placed in Turkey in 1961 could reach Moscow in about 15 minutes—much more quickly than any existing Russian missiles could reach New York or Washington, D.C.
The U.S.S.R. retaliated by placing missiles in Cuba. With typical Cold War logic, Nikita Khrushchev thought it was only fair for the Soviet Union to situate missile sites near the U.S. coast, since the U.S. had done the same with his country. However, he grossly miscalculated by placing these missiles in a nation that had so recently been a U.S. ally—and he was probably unprepared for the fierce American response.
The height of the crisis came in October 1962. On October 24, President Kennedy authorized a naval blockade of Cuba, with the intent of intercepting any more nuclear missile shipments from the U.S.S.R. Over the next two days, tensions quickly escalated, with many diplomats working behind the scenes to broker a deal (for example, by each side agreeing to remove its missiles from Turkey and Cuba).
Both sides stepped down from the brink. On October 28, in a radio address, Khrushchev informed U.S.S.R. citizens that he had agreed to remove the nuclear missiles from Cuba. What he could not reveal was that the U.S. had also (and secretly) agreed to remove its missiles from Turkey, which most citizens in both countries were unaware even existed!
Within two years, both leaders were gone. Barely a year after the Cuban Missile Crisis, President Kennedy was assassinated in Dallas, while Khrushchev was deposed in 1964 and replaced by Leonid Brezhnev—partly, historians believe, because of the embarrassment (and loss of prestige to the U.S.S.R.) his Cuban adventure had precipitated.