Today's Geo Quiz deals with a tussle over the new Tube map in London. The city's latest map of the London Underground excludes an image of the Thames River, and that's ruffled some feathers. We asked you to name some other cities where the local subway map leaves out a major river. The cities we were looking for are Berlin, Madrid, Osaka, Bilbao, Beijing, Stockholm, Valencia, Guangzhou, Shanghai, and Chicago. Anchor Marco Werman speaks with Mark Ovenden, author of Transit Maps of the World.