Part of Transport for London's Art on the Underground project, tube maps have been an ongoing showcase of the hottest contemporary artists around since 2004.
Emma Kay, August 2004:
David Shrigley, October 2005:
Liam Gillick, January 2007:
Richard Long, September 2009:
Eva Rothschild, March 2011:
Yayoi Kusama, December 2011: