Comment Re:Royal Mail - Doing it in London years ago (Score 3, Interesting) 117
Here you go. My understanding is that London is full of all sorts of tunnels built for various purposes. From the huge Victorian era sewage system to the London Underground and various utility tunnels. Chatting to engineers, one of the issues they have building anything in London is that often you'll encounter some uncharted tunnel. Odd though this may sound, I have exploring London's underground tunnels on my bucket list.