Want to live in a hole in the ground? Not a nasty wet hole, nor a dry sandy hole? Obviously, you’re not alone. There’s even a hobbit motel. Now that means comfort. Check out this selection of 15 green-roofed dwellings that take a page right out of Tolkien’s books and come in all sizes for all kinds of functions, from hotels in New Zealand to backyard playhouses and vintage underground hill-dug duplexes.