The formidable Seigried line, didn't come into play prior to Nazi Germany's invasion of France so it was substantially disassembled to build the Atlantic Wall. Five years later after D-Day Germany desperately attempted to refortify the decayed, disassembled and somewhat obsolete defenses. Battle focuses on Aachen where the allies employ withering fire power but become stalled leading Germany to squander its remaining military strength in the Battle of the Bulge leaving the Sigfried line open to a rapid crossing by the allies.
—David Foss