D-Day D-Day is the most well-known, gruesome day in the history of WWII. Out of the five landings, the landing on Omaha Beach was, by far, the worst for the U.S. and The Allies. Paratroopers who had landed the night before came up behind the Germans and aided the U.S. and The Allies. Eventually they pushed through and invaded Hitler’s Europe. Even though D-Day was considered a massacre, the invasion aided the US’s ultimate victory. D-Day happened on June 6, 1944. It was one of the darkest days in the history of World War II, not only for t ....