The Westwall was a series of fortifications constructed between 1938 and 1940 along the western frontier of Germany between the Netherlands and Switzerland.
In WWII the Allies called it the Siegfried Line.
After Germany invaded Belgium in May 1940, the line was no longer garrisoned and was neither maintained nor updated (e.g. to house new weapons like the MG42 or Schwere Park Heavy Anti-Tank Gun). After the Allied Invasion at Normandy, the neglected line was re-activated and manned from about 10th September 1944 (just a few days before the US Army reached it!). It took until February 1945, following the failure of the German Ardennes offensive, for the whole of this section to be fully in American hands.
A nearby War Cemetery bears witness to the many lives lost in conquering the Wall.
These pictures all come from the area facing Belgium, to the southeast of Aachen. The section of the line here was designed to stop upto 36tonne tanks. To the east (rear) of the wall a full series of bunkers, shelters, observation posts and other fortifications were built. Pictures of these must wait until another visit!