This photo, shared by Flickr user IsarSteve, shows an absolutely amazing discovery. Construction work at the Knightsbridge Underground station in 1996 uncovered this stunning 1949 quad royal* poster of the Tube map. It looks as if the workers know they’ve found something wonderful as well, judging by the yellow and black warning tape surrounding the frame.

For many, the 1949 tube map is the apotheosis of the Beck style, with his ruthless quest for simplification and order at its height. The Central Line blazes a red, totally horizontal path across the middle of the map, and as much else as possible is reduced to horizontal or vertical lines only; diagonal lines are only used where absolutely necessary. This does present one small problem in that Kew Gardens and Richmond stations on the far southwestern branch of the District Line are nowhere near the Thames, as they are in real life.

*Quad royal simply refers to the paper size, being the same size as four sheets of Royal paper, or 50 inches wide by 40 inches deep.

Source: IsarSteve/Flickr