On June 6, 1944, the D-Day operation brought together the land, air, and sea forces of the allied armies in what became known as the largest amphibious invasion in the history of warfare. The Allies used over 5,000 ships and landing craft to land more than 150,000 troops on five beaches in Normandy. The landings marked the start of a long and costly campaign in north-west Europe, which ultimately convinced the German high command that defeat was inevitable. The invasion was a combined naval, air, and land assault on Nazi-occupied France. Allied airborne forces parachuted into drop zones across northern France, and ground troops then landed across five assault beaches - Utah, Omaha, Gold, Juno, and Sword. Troops leapt from their landing boats and were pinned down for hours by murderous machine-gun fire that turned the beach into a vast killing field. By the end of the day, the Allies had established a foothold along the coast and could begin their advance into France. The defeat of Germany was acknowledged as the western Allies’ principal war aim as early as December 1941. Opening a second front would relieve pressure on the Soviet Union in the east, and the liberation of France would weaken Germany’s overall position in western Europe. The invasion, if successful, would drain German resources and block access to key military sites. The decision to go ahead with the invasion was one of the gutsiest decisions of the war.