The term refers to the December 16, 1944, German confrontation with the American forces in the Ardennes Mountains, a forested plateau range that extends from northern France into Belgium and Luxembourg. Even though Germany appeared to be beaten at this late point in the war, Hitler rallied his remaining forces and launched a surprise assault on the American soldiers in Belgium and Luxembourg. But Germany could not sustain the front, and within two weeks the Americans had halted the German advance near Belgium’s Meuse River (south of Brussels). The offensive became known as the Battle of the Bulge because of the protruding shape of the battleground on a map.

The Ardennes were also the site of conflict earlier in World War II, in 1940, as well as in World War I, in 1914 and 1918.