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 found in Cusco and the Temple of the Sun found in Pisac, in having what Bingham described as a "parabolic enclosure wall". The stonework is of ashlar quality. Within the temple is a 1.2 m by 2.7 m rock platform, smooth on top except for a small platform on its southwest quadrant. A "Serpent's Door" faces 340°, or just west of north, opening onto a series of 16 pools, and affording a view of Huana Picchu. The temple also has two trapezoidal windows, one facing 65°, called the "Solstice Window", and the other facing 132°, called the "Qullqa Window". The