Editor's note: We climbed the Pyramid of the Sun before authorities stopped allowing visitors to do so, and here’s the scoop: when you’re there you feel, unbidden, the layers and layers of Mesoamericans who inhabited this great city, and the hair-raising events (human and animal sacrifice) that occurred there. Although it’s open and blasted by the sun and wind, it feels crowded, in the most interesting way. It’s worth a visit, but get yourself some stunning Teotihuacan wallpapers in the meantime!