A gigantic undertaking that stretched the creative and technological genius of the Allied forces, D-Day was perhaps the most dramatic single event of World War II. Using rarely seen archival sources and oral histories of combatants, D-Day presents the brave young soldiers who brought with them the innocent belief that all things were possible.

While a phony assault was being acted out on Calais, complete with dummy landing craft and thousands of rubber tanks and trucks, the real assault took place on the beaches along a 50-mile stretch of fortified coastline in Normandy. Three thousand war ships carried 200,000 armed men and nearly 30,000 vehicles across one of the most unpredictable and dangerous seas in the world, in the worst Channel weather of the century. Given the code name "Overlord," it was an operation so mammoth that once in motion, there was no turning back.

"It was a soldier's battle," Eisenhower said later. For all the split-second planning and careful rehearsal, it came down to the young men whose remembrances and recollections provide the heart of this documentary.

The single biggest and bloodiest battle American soldiers ever fought. It came as a total surprise, on December 16th, 1944, when 30 German divisions roared across the Allied front in Belgium and Luxembourg. The war, after all, was coming to an end. Allied commanders were eating oysters, celebrating promotions, and reflecting on the death of Glenn Miller. This was Hitler's final gamble and for the more than half a million men thrown into the cause, an infernal test of courage and endurance.