Niki Feijen is a dutch photographer who has found the special and spectacular subject of abandoned places. They consist of abandoned churches, factories, amusement parks, prisons, and estates.
I recommend checking out his site and then you can turn to google images and hunt down abandoned 'whatevers'. I suggest whatevers: boilers, water parks, amusement parks, trains, estates, and factories. (If
you find a fascinating one please tell us!)
I've spent three evenings studying amazing places. A lot of them scream things like 'Half Life' scene and whatnot.
To start you off here's a link to the master's collection.
http://500px.com/nikifeijen