Tree houses, yurts, modified Airstream trailers and other alternative shelters are making a big-city comeback as the “glamour camping” trend moves into urban centers around the world. As to the appeal of urban glamping—well, any child of the city or the suburbs who ever “camped” in the back yard on a summer night can understand. You’re right in the middle of it all: hearing snatches of city noise, grazing on easy-to-replenish food supplies, and sleeping under the stars, in a comfy bed that someone else will make up the next morning.