Operation Overlord was the code name for the Allied invasion of Normandy on June 6, 1944 during World War II. It involved over 150,000 Allied troops storming the beaches of Normandy that were held by German forces. The operation was planned by American General Dwight Eisenhower and involved troops from the United States, Britain, Canada, and Free French forces. It resulted in tens of thousands of casualties but succeeded in gaining a foothold for the Allies in German-occupied France and helped lead to the eventual defeat of Nazi Germany.