The cuban missile crisis, also known as the October crisis was a 13 day confrontation in October 1962 between the United States and the Soviet Union over soviet ballistic missiles deployed in Cuba. President Kennedy did not dare to invade Cuba, because that action could have started a world war - yet he could not let the missile sites be completed. With his advisers, he decided on a naval blockade to prevent Russian ships delivering the missiles for the Cuban sites.
