Roosevelt Island Between Manhattan and Queens used to be dedicated to prisons, asylums and hospitals. I still know of 2 abandon sites, one is on the southern tip. That whole island is weird though. Growing up i knew no normal people who grew up there.
I'm sorry but as an artist i think this guy is a tool. Granted he his a self promoting tour de force, which i guess all art has become in the present day. Anyway here's another article about where he gets his ideas from.
You guys really do bend over and smell your own farts.
http://www.art-for-a-change.com/Obey/index.htm