America played a key role in ending World War 2 through major military operations like the D-Day invasion of Normandy and the bombing of Hiroshima and Nagasaki with atomic weapons. The D-Day invasion on June 6, 1944 saw over 150,000 American, British, and Canadian forces land in Normandy to open a Western Front against Nazi Germany. In August 1945, the United States dropped atomic bombs on the Japanese cities of Hiroshima and Nagasaki, the first nuclear weapons ever used in warfare, leading to Japan's surrender and the end of World War 2.