D-Day was a massive Allied operation that launched the invasion of German-occupied western Europe during World War II. On June 6, 1944, over 150,000 American, British, and Canadian forces landed along a 50-mile stretch of the Normandy coast of France. The massive operation involved thousands of ships and over 100,000 troops storming five beaches, despite facing stiff resistance from German forces. It marked the beginning of the liberation of German-occupied northwestern Europe from Nazi control.