D-Day marked the beginning of the Allied invasion of German-occupied western Europe during World War II. On June 6, 1944, over 150,000 American, British, and Canadian forces landed along five beaches of Normandy, France, facing German opposition. The invasion began with airborne assaults behind German lines and troops landing under fire at beaches like Omaha Beach, where terrain allowed Germans to target exposed soldiers. Although the invasion resulted in heavy casualties, by week's end the Allies had secured 50 miles of coastline in France. The invasion of Normandy on D-Day set the stage for the two-month Battle of Normandy and the eventual Allied victory in Europe.