"feral houses" abandoned buildings in Detroit that are being reclaimed by nature. Along with the 100 Abandoned Houses project (also in Detroit). Maybe just empty things, so there's one site that's full of all the empty spaces we've got.
Nature colonizes everything. Abandoned library with tree. I would love to have a thing of nature in a library it just seem so cool. I mean you can read your book on the tree! Even though it's abandoned that would be awesome.