Battle of the Bulge

The Battle of the Bulge (16 December 1944 – 25 January 1945) was a major German offensive campaign launched through the densely forested Ardennes region of Wallonia in Belgium, France and Luxembourg on the Western Front toward the end of World War II in Europe. The surprise attack caught the Allied forces completely off guard and became the costliest battle in terms of casualties for the United States, whose forces bore the brunt of the attack, during all of World War II. It also severely depleted Germany's war-making resources.

• http://en.wikipedia.org/wiki/Battle of the Bulge