Early in the morning on September 5th, 1972, eight members of Black September, a Palestinian terrorist organization snuck into the Olympic Village in the 1972 Munich Olympics.
They raided the building that housed the Israeli olympians. They killed two in the raid, and they took nine into hostage.
After spending the rest of the day trying to negotiate for an exchange of prisoners for hostages, the Black September members realized their demands were not going to be met, and they requested a plane ride to Egypt.
German officials couldn't let terrorists leave the country with hostages, so they prepared a rescue attempt. The rescue attempt failed and all nine of the Israeli hostages were killed during the shoot-out. Five of the Black September were killed, and the other three were taken into custody.