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
Ancient Ruins and Archaeology Quarterly", and "Travel". The work is a guide to a dozen of the more famous ruins from civilizations of ancient times throughout the world, the speculations surrounding their fates, and modern fantasy literature inspired by them. The surveyed sites include Tartessos, the Pyramids of Giza, Stonehenge, Troy, Ma'rib, Zimbabwe, Tintagel, Angkor, the Mayan city of Tikal, the Inca city of Machu Picchu, Nan Matol, and the Moai of Rapa Nui. Francis D. Lazenby, in the "Library Journal", called the book a "highly literate volume" whose "fascinating" accounts "are not simply another retelling: unusual material is added, and in very readable