The battles for the Germans' last line of defence in World War II, including Arnhem, Aachen, the Huertgen Forest, and Metz. Built as a series of forts, bunkers, and tank traps, the West Wall - known as the Siegfried Line to the Allies - stretched along Germany's western border. After D-Day in June 1944, as the Allies raced across France and threatened to pierce into the Reich, the Germans fell back on the West Wall. In desperate fighting - among the war's worst - the Germans held off the Allies for several months.