There are 3D tube maps: http://brunoimbrizi.com/experiments/#/07 http://brunoimbrizi.com/experiments/#/07 https://vimeo.com/67869313 https://vimeo.com/6786931

There are 3D tube maps: http://brunoimbrizi.com/experiments/#/07 http://brunoimbrizi.com/experiments/#/07 https://vimeo.com/67869313 https://vimeo.com/67869313 (last one seems to be only available as a video) Also, just as a tangential point, you may be interested in the BBC documentary from last week about underground spaces in Rome, which was excellent. It's called "Rome's Invisible City", and there are a couple of copies on youtube: https://www.youtube.com/watch?v=6QAaYi0Zt4I https://www.youtube.com/watch?v=6QAaYi0Zt4I