S1, E4: In the early hours of June 6, 1944 - D Day - the invasion of France begins. A million and a half men take part. It is the bloodiest day in American history since the Civil War. The Allies succeed in tearing a 45 mile gap in Hitler's vaunted Atlantic Wall. By day's end more than 150,000 men have landed on French soil, and more men and more equipment and supplies are coming ashore every hour.