Inca Trail to Machu Picchu terminus at the Sun Gate on Machu Picchu mountain. The two longer routes require an ascent to beyond above sea level, which can result in altitude sickness. Concern about overuse leading to erosion has led the Peruvian government to place a limit on the number of people who may hike this trail per season, and to sharply limit the companies that can provide guides. As a result, advance booking is mandatory. A maximum of 500 people are allowed on the trail each day, of which only 200 are trekkers, the rest being guides and porters. As a result, the high
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