In 1931 Harry Beck, an engineering draughtsman working for the London Underground, drew a map of it in his spare time: every line straight, every bend at forty-five degrees, the stations spaced out evenly, as if the city were a circuit board. It is wrong about nearly everything a map is usually for, distances, directions, the real wanderings of the river. The Underground’s managers doubted passengers would accept it and printed a small trial run in 1933. The public took to it at once, because underground you can’t see the landscape anyway; all you need is the order of the stops and where to change. It has been believed for so long that people still ride the single stop from Leicester Square to Covent Garden, two stations a few minutes’ walk apart, because down there the map is the only London they have.