Funny if you're from Lahndan

Tunnel Vision
The pedestrian subway systems under Marble Arch, the north side of Blackfriars Bridge and the southern end of Tottenham Court road were designed and built by the Ministry of Works in the Spring of 1940. Their intention was to confuse and demoralise as much of an invading enemy army as they could - it was estimated that as many as five Wehrmacht divisions could be tied down and destroyed by attrition in each system by a force as small as eight Evening Standard vendors.

From the very marvellous This Isn't London. Cheers, David.