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.
Noah's Ark is a Sustainable Floating City for a Post-Apocalyptic World
The burdei dates back as far as 6000 years and it’s a type of half-dugout shelter somewhat between a sod house and a log cabin, usually with a floor that’s 1 – meters under ground level. Not realy a tree house but still cool