Lost city Inca site situated on a mountain ridge above the Urubamba Valley in Peru. Often referred to as the "Lost City of the Incas", it is perhaps the most familiar icon of the Inca World. Machu Picchu was built around 1450, at the height of the Inca Empire. It was abandoned just over 100 years later, in 1572, as a belated result of the Spanish Conquest. It is possible that most of its inhabitants died from smallpox introduced by travelers before the Spanish conquistadors arrived in the area. In 1911, Melchor Arteaga led the explorer Hiram Bingham to Machu Picchu, which
Machu Picchu the sun rise. Architecturally, Inti Mach'ay is the most significant structure at Machu Picchu. Its entrances, walls, steps and windows are some of the finest masonry in the Incan Empire. The cave also includes a tunnel-like window unique among Incan structures, which was constructed to only allow sunlight into the cave during several days around the December solstice. For this reason, the cave was inaccessible for much of the year. Inti Mach'ay is located on the eastern side of Machu Picchu, just north of the "Condor Stone." Many of the caves surrounding this area were prehistorically used as tombs, yet