Overview: This is the story of the construction and defence of Hitler's three-mile deep web of fortifications, pillboxes, troop shelters, and anti-tank obstacles that ran along Germany's western frontier. "The Siegfried Line," as it was nicknamed by the Allies, and the natural barrier formed by the Rhine River, were key to Germany's defence of its Western Front. The breaching of the Siegfried Line at the Battle of the West Wall, and the subsequent crossing of the Rhine barrier at Remagen, heralded the collapse of German resistance in the West.