underground

First, there's a website about disused London Tube Stations with lots of pictures.

                             Then, there is <a href="http://www.heritagemagazine.co.uk/underground.html">The Underground City</a>, more about London's tunnels from a                                 historical point of view. Both websites are quite fascinating. [via <a href="http://radio.weblogs.com/0113064/">cartonist</a>]