From Eduardo Paolozzi's Tottenham Court Road mosaics to Mark Wallinger's 270 labyrinths: the tube network is packed with works by some of the world's biggest artists.
On 24 July, TfL is hosting free 90-minute guided art tours of the network, taking in many of these masterpieces.
Tours start at St James's Park station at 11pm, 1pm and 3pm, finishing at Edgware Road station. Pre-booking is essential. For tickets email firstname.lastname@example.org
The tours coincide with the launch of the Art Tube Map, the first comprehensive guide to art works on the underground. Keep your eyes peeled for copies in all zone 1 stations.