1984 - In Washington, DC, terrorists bombed the Washington Navy Yard Officers Club.
1999 - Thirteen people were killed at Columbine High School in Littleton, CO, when two teenagers opened fire on them with shotguns and pipebombs. The two gunmen then killed themselves.
1920 - In Starkville, MS, and Waco, AL, 88 people were killed by a tornado.
1967 - In Nicosia, Cyprus, 126 people died when a chartered Swiss Globe Britannia Turboprop crashed while landing.
2010 - In the Gulf of Mexico, the Deepwater Horizon oil platform exploded. Eleven workers were killed.
1978 - The Korean Airliner Flight 902 was shot down while in Russian airspace. Two passengers were killed when the plane landed on a frozen lake.
Tomorrow in Disaster History.