1944 — World War II: Commencement of Operation Overlord: The Allied invasion of Normandy begins with the execution of Operation Neptune—commonly referred to as D-Day—the largest seaborne invasion in history. Nearly 160,000 Allied troops cross the English Channel with about 5,000 landing and assault craft, 289 escort vessels, and 277 minesweepers participating. By the end of the day, the Allies have landed on five invasion beaches and are pushing inland.