D-Day is a military term that states for the day on which a combat attack or operation is to be started. The initiation of the Battle of Normandy (it took place on the 6th of June, 1944) is usually referred to as just D-Day, as it is the best known event of a kind in military history.

It began with overnight parachute and glider landings, massive air attacks and naval bombardments. By the end of August the northern France was liberated from Germany. Later the invaders were reorganized and set off for Germany. They joined the efforts with the Soviet forces, which were coming from the east, and together brought an end to Hitler's Reich.

Most historians estimate that the operation cost the Alliance about 2,000 casualties, but some researchers suggest that twice as many people were left dead.

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