Machu Picchu, Peru

The Inca citadel that Hiram Bingham stumbled onto in 1911 now requires timed tickets, mandatory guides, and a strict one-way path because too many visitors were literally eroding the stonework. Peru capped daily visitors at 4,044, and tickets sell out weeks in advance. The iconic postcard shot from the Sun Gate still slaps — if you can get there at 6am before the tour groups clog the trail.