NYC's Roosevelt Island has a fascinating history and many secrets, from former lunatic asylum, abandoned hospital, underground tunnels and quirky statues.
10 of NYC's abandoned hospitals, a remnant of a darker past when the diseased and undesirables were placed far from civilization, by Will Ellis of Abandoned NYC
Here is a gkibak list of ten lesser-known historical ruins including the only one in New York City–Renwick Smallpox Hospital on Roosevlet Island.
Our most popular list on Foursquare is our Abandoned NYC list. Some places are break-in-able, some open to the public, some only for the intrepid.