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 more farmland to grow crops, and to steepen the slopes that invaders would have to ascend. The terraces reduced soil erosion and protected against landslides. Two high-altitude routes from Machu Picchu cross the mountains back to Cusco, one through the Sun Gate, and the other across the Inca bridge. Both could be blocked easily, should invaders approach along them. The site is roughly divided into an urban sector and an agricultural sector, and into an upper town and a lower town. The temples are in the upper town, the warehouses in the lower. The architecture is adapted to the mountains.