June 6, 1944–the greatest machine of World War Two springs into action. It is made up of thousands of ships and aircraft, tens of thousands of men and millions of tons of steel and concrete. This is Operation Overlord–the invasion machine that will send Allied soldiers dropping from the skies and storming the beaches of Normandy. Each piece of this machine has been designed to fulfill a specific task in the air, on land, or at sea. The success of D-Day depends on it. Interlocking with pinpoint precision, the men and machines of Overlord overcome not just Hitler’s beach defenses, but nature itself in the greatest assault the world has ever seen. Using archive film, and color reenactments, we reveal the phenomenal hardware of D-Day.