June 6 marks the 80th anniversary of the Allied invasion of Normandy, France, in 1944. Code-named Operation Overlord, it was a massive logistical effort involving nearly 156,000 American, British, Canadian, free French, and Polish troops landing on five beaches along the coast of France.
The invasion required advances in engineering and logistical planning as well as coordination of thousands of troops, ships, and aircraft to make it work.
