This used to be illegal, I think, but some clever guys with far too much time on their hands have used GPS technology, the freedom of information act and data released under a creative commons to create maps of the London tube network, as the lines physically are underground – as in not in the nice, ordered layout that makes it one of the best and simplest maps in the world – but how the tunnels actually cut through the earth below.
My friends Seany and Joe, this is for you especially.
Check it out. Awesome.