(Monday, January 17, 1966, at about 10:30 a.m. UTC; during the Cold War) — A U.S. Air Force B-52 carrying four unarmed hydrogen bombs crashed today near the Spanish coastal town of Palomares after colliding with a jet tanker.

Fortunately, no nuclear explosion was triggered, but all four of the men on board the tanker were killed, and only four of the seven men on the B-52 were able to parachute to safety.

Three of the bombs were quickly recovered, but the fourth wasn’t recovered until April 1966.