Bolt Action - The Longest Day D-Day - Battle SetYears of planning culminate in The Longest Day, the long awaited invasion begins with the assault on the beaches of Normandy; D Day 6th June 1944 The longest day Normandy, 6 June 1944. The Allies undertake the largest and most ambitious amphibious landings in history to return the fight to western Europe. Re create the turning point of the war, that allowed the Allies to gain a foothold in Europe and which was to set the stage for the Axis downfall.