Operation Overlord was the codename for the Battle of Normandy, the Allied operation that launched the successful liberation of German-occupied Western Europe during World War II. The operation was launched on 6 June 1944 (D-Day) with the Normandy landings. A 1,200-plane airborne assault preceded an amphibious assault involving more than 5,000 vessels. Nearly 160,000 troops crossed the English Channel on 6 June, and more than two million Allied troops were in France by the end of August.
LSTs with barrage balloons deployed, unloading supplies on Omaha Beach for the breakout from Normandy
US Army M4 Sherman tanks loaded in a landing craft tank (LCT), ready for the invasion of France, c. late May or early June 1944
D-day assault routes into Normandy
Air plan for the Allied landing in Normandy
The Allies, formally referred to as the United Nations from 1942, were an international military coalition formed during World War II (1939–1945) to oppose the Axis powers. Its principal members by the end of 1941 were the "Big Four" – United Kingdom, United States, Soviet Union, and China.
The Allied leaders of the European theatre (left to right): Joseph Stalin, Franklin D. Roosevelt and Winston Churchill meeting at the Tehran Conference in 1943
The Allied leaders of the Asian and Pacific Theater: Generalissimo Chiang Kai-shek, Franklin D. Roosevelt, and Winston Churchill meeting at the Cairo Conference in 1943
French postcard illustrating the alliance between Poland, France and the United Kingdom (1939)
"Long live the victory of the Anglo-Soviet-American military alliance!" – USSR stamp of 1943, quoting Stalin
