The Normandy landings were the landing operations and associated airborne operations on Tuesday, 6 June 1944 of the Allied invasion of Normandy in Operation Overlord during World War II. Codenamed Operation Neptune and often referred to as D-Day, it was the largest seaborne invasion in history.
The operation began the liberation of France (and later western Europe) and laid the foundations of the Allied victory on the Western Front.
Planning for the operation began in 1943. In the months leading up to the invasion, the Allies, an international military coalition formed during to oppose the Axis powers, led by Nazi Germany, Imperial Japan, and Fascist Italy, conducted a substantial military deception, codenamed Operation Bodyguard, to mislead the Germans as to the date and location of the main Allied landings.
The weather on D-Day was far from ideal, and the operation had to be delayed 24 hours; a further postponement would have meant a delay of at least two weeks, as the invasion planners had requirements for the phase of the moon, the tides, and the time of day that meant only a few days each month were deemed suitable.
The Allies failed to achieve any of their goals on the first day. Carentan, Saint-Lô, and Bayeux remained in German hands, and Caen, a major objective, was not captured until 21 July. Only two of the beaches (Juno and Gold) were linked on the first day, and all five beachheads were not connected until 12 June; however, the operation gained a foothold that the Allies gradually expanded over the coming months.
German casualties on D-Day have been estimated at 4,000 to 9,000 men. Allied casualties were documented for at least 10,000, with 4,414 confirmed dead. Museums, memorials, and war cemeteries in the area now host many visitors each year.