In October 1962, the U.S. discovered that the Soviet Union was constructing secret nuclear missile sites in Cuba, sparking a 13-day confrontation that brought the superpowers to the brink of nuclear war. President John F. Kennedy responded by establishing a naval “quarantine” around the island and demanding the immediate removal of all offensive weapons. Soviet Premier Nikita Khrushchev initially denounced the blockade, but as tensions escalated, he offered to withdraw the missiles in exchange for a public pledge that the U.S. would not invade Cuba.