I had a day off today to head into London to go on a Hidden London tour of Charing Cross station.
It was interesting to see the unused platforms and tunnels, and some of the ventilation system. It was also interesting to hear about how the platforms and escalators that are hidden behind unassuming doors were used in films like Skyfall (see an excerpt here)
The visit into the ventilation system gave this interesting photo opportunity, down onto the platforms.
There are a couple of extras, and a good few more on Flickr.