Machu Picchu transport of this obsidian type in pre-Hispanic Peru. Thousands of tourists walk the Inca Trail to visit Machu Picchu each year. They congregate at Cusco before starting on the one-, two-, four- or five-day journey on foot from kilometer 82 (or 77 or 85, four/five-day trip) or kilometer 104 (one/two-day trip) near the town of Ollantaytambo in the Urubamba valley, walking up through the Andes to the isolated city. Machu Picchu is both a cultural and natural UNESCO World Heritage Site. Since its discovery in 1911, growing numbers of tourists have visited the site each year, including 1,411,279 in 2017.
Machu Picchu prevent it from running down the mountain. Similar layering protected the large city center from flooding. Multiple canals and reserves provide water throughout the city that could be supplied to the terraces for irrigation and to prevent erosion and flooding. The Incas never used wheels in a practical way, although their use in toys shows that they knew the principle. The use of wheels in engineering may have been limited due to the lack of strong draft animals, steep terrain and dense vegetation. The approach to moving and placing the enormous stones remains uncertain, probably involving hundreds of men to