http://en.wikipedia.org/wiki/Tube_map
The first diagrammatic map of London’s rapid transit network was designed by Harry Beck in 1931. Beck was a London Underground employee who realised that because the railway ran mostly underground, the physical locations of the stations were irrelevant to the traveller wanting to know how to get to one station from another – only the topology of the railway mattered…
London Underground was initially sceptical of his proposal – it was an uncommissioned spare-time project, and it was tentatively introduced to the public in a small pamphlet in 1933. It immediately became popular, and the Underground has used topological maps to illustrate the network ever since.
Despite the complexity of making the map, Beck was paid just five guineas for the work.