The London Underground map designed by Harry Beck in 1931 was so revolutionary in concept that, when London Transport first distributed it, they fully expected the public to reject it. How wrong could they be? It was readily appreciated for its bold simplicity, and for the fact that it got you from A to B.

Its main innovation lay in the way it makes free with the realities of geography, as though underground was subject to different spatial laws to the outside world. The design appears on official merchandise all over the place, from mugs to tea-towels, making it as widely reproduced as certain works of modern art.