The Siegfried Line (German: Westwall) was a line of fortifications erected by the government of Nazi Germany in the 1930s to protect its western frontier with France and Belgium; it ran largely parallel with the French Maginot Line, extending from Kleve (near the Dutch city of Nijmegen) to the Swiss border. During the early days of the Second World War (the so-called Phony War) the line was mocked in a British popular song:
We're going to hang out the washing on the Siegfried Line.
Have you any dirty washing, mother dear?
We're gonna hang out the washing on the Siegfried Line
'cause the washing day is here.