On that day, John F. Kennedy announced to the American people that the Cuban Missile Crisis was underway, an explosive revelation that the Soviet Union had secretly deployed nuclear-armed missiles on the island of Cuba, only 90 miles from the U.S. mainland. The map above captures the gravity of that confrontation: Soviet intermediate-range ballistic missile bases in Cuba, U.S. naval and air “quarantine” (blockade) zones around the island and the looming threat circle stretching deep into the continental United States.