The Cinder Cone is the ultimate treehouse, and it wasn’t even built for kids. Foster Huntington and his pals built these two treehouses in Washington State, which are connected via a little wooden bridge. Windows all around the higher treehouse allow 360° views of the surrounding countryside, as well as a birds-eye view of the amazing skate bowl below! Inside, the treehouses are minimally decorated and have working and relaxing spaces for their inhabitants. Oh, and when they really need to relax, Foster and his friends also have heated outdoor baths to enjoy. Pretty luxurious, right? You can follow the story of the Cinder Cone and more on Foster Huntington’s blog.