The abandoned Glenn Dale Hospital in Maryland would be on my wish list of places to explore if it was cleaned up a little and open to the public. I know, an urban explorer I am not!

http://www.dailymail.co.uk/news/article-2763803/Empty-morgues-abandoned-wards-corridors-overrun-ivy-Inside-deserted-Maryland-tuberculosis-sanatorium-children-deadly-infection-left-isolated-say-s-haunted.html

http://www.wtop.com/541/3718241/Ghost-Tales-Inside-Glenn-Dale-Hospital