Demolition of the Paris Metro, definitely one of the best photo essays I have ever seen! After reading that one, I spend another hour or more on the site. The site is very well done, and the photography is amazing!
I have always been interested in those old places, the places your not supposed to go, abandoned, etc. But I am not so adventurous to go to a lot of those types of places, well at least not the ones that I would like to go to!