"The London Underground As Air Raid Shelter, London, England, 1940" One of London's most popular shelters is that which is to be found in a section of the London underground system which has been converted by tearing up the tracks. The advertisements remain pasted on the wall. Hats and coats are hung on nails which have been driven in between the bricks on the wall. People sleep on the platform and on the space whcih was formerly the track, this part stretching for a quarter of a mile.