The extraordinary ruins of Machu Picchu, at an elevation above 2400 m, were among the most amazing creations of the Inca Empire at its height: its giant walls, terraces and ramps seem to have been cut out of continuous rock…

The extraordinary ruins of Machu Picchu, at an elevation above 2400 m, were among the most amazing creations of the Inca Empire at its height: its giant walls, terraces and ramps seem to have been cut out of continuous rock…