D-Day
June 6, Thursday
In the military, D-Day is the day on which a combat attack or operation is to be initiated. The best-known D-Day is during World War II, on June 6, 1944—the day of the Normandy landings—initiating the Western Allied effort to liberate western Europe from Nazi Germany. However, many other invasions and operations had a designated D-Day, both before and after that operation.