On Wetherill Mesa, the magnificent Long House is the second-largest cliff dwelling in the park. A strenuous place to visit, it is only reached as part of a ranger-led guided tour (organized from the visitor center). Access involves climbing three ladders – two at 15ft and one at 4ft. The 0.75-mile round-trip hike has a 130ft elevation change. You have to book your tickets in person, with up to two days advance purchase allowed.