The Battle of the Bulge, also known as the Ardennes Offensive, was a major World War II battle fought from December 16, 1944 to January 25, 1945. It was the largest and bloodiest battle of the war for the United States, with over 80,000 casualties. The battle was a surprise attack by the German forces in the Ardennes forest of Belgium and Luxembourg, and is considered to be one of the last major German offensives of the war.