Machu Picchu in South America, one of the most visited tourist attractions in Latin America and the most visited in Peru. Machu Picchu has wet and dry seasons, with the majority of annual rain falling from October through to April. Machu Picchu is situated above a bow of the Urubamba River, which surrounds the site on three sides, where cliffs drop vertically for to the river at their base. The area is subject to morning mists rising from the river. The location of the city was a military secret, and its deep precipices and steep mountains provided natural defenses. The Inca Bridge,
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