Eighty years ago, on the beaches of Normandy, northern France, an event unfolded that would alter the course of history. The day was June 6, 1944, a date forever etched in time as D-Day. It marked the launch of Operation Overlord, the ambitious Allied invasion of western Europe that became a turning point in World War II. The audacious assault by sea, air and land involved nearly 160,000 troops mainly from the USA, Britain and Canada.