During World War II (1939-1945), the Normandy landings, codenamed Operation Neptune, was a major hit to Nazi Germany. It was the landing of Allied forces on the coast of France, which took place on June 6, 1944, a day also known as D-Day.
That day, about 156,000 American, British and Canadian forces landed on five beaches along a 50-mile stretch of the heavily fortified coast in the Normandy region of France.
The Battle of Normandy, or Operation Overlord that followed, ended on August 19, 1944, when Allied troops crossed the Seine. Major General Dwight D. Eisenhower was appointed commander-in-chief of the entire operation.
By the end of August 1944, all of northern France had been liberated, and the following spring the Allies had defeated the Germans. The Normandy landings have been called the beginning of the end of war in Europe.
Source: Wikipedia, history.com