John F. Kennedy was the President of the USA in the early 1960s. He was totally opposed to the spread of Communism. Two years after he became President a major Cold War crisis erupted involving the island of Cuba, which was very close to the USA mainland.
In the early 1960s, Cuba had become a Communist state and was led by Fidel Castro. Cuba began to develop close ties with the USSR and this caused problems for the new USA President. Kennedy and his military advisors planned an invasion of Cuba involving Cuban exiles living in the USA. This took place at the Bay of Pigs but was a complete disaster for the USA. As a result of this, Castro began to develop even closer economic and military links with the USSR and its leader, Khrushchev.
In 1962 a USA U2 spy plane took photos of a missile launch site being built in Cuba. This caused mass panic in the USA. Also ships from the USSR were heading in the direction of Cuba with what looked like parts of missiles. President Kennedy then came under pressure from one group of military advisors who wanted to bomb the missile sites and another group who wanted to set up a naval blockade around the island. In the end Kennedy ordered a blockade to be set up to prevent these ships getting to Cuba. This created a very tense situation and many people were certain it could lead to a nuclear war between the USA and the USSR. After a few days, both sides backed down and a deal was made, which put an end to a very dangerous situation