Cusco

Machu Picchu is a pre-Columbian Inca site located 2,430 meter (8,000 feet) above sea level. Often referred to as "The Lost City of the Incas", Machu Picchu is located in the Cusco Region of Peru, the Incas started building it around 1430 AD and has been declared a World Heritage Site by UNESCO in 1983.

Machu Picchu was built with polished dry-stone walls. Its primary buildings are the Intihuatana, the Temple of the Sun, and the Room of the Three Windows.

This city is situated above a loop of the Urubamba River that surrounds the city on three sides, with cliffs dropping vertically for 450 meter (1,500 feet) to the river below. The location of the city was a military secret, and its deep precipices and mountains provide excellent natural defenses. An Inca rope bridge across the Urubamba River in the Pongo de Mainique, provided a secret entrance for the Inca army. Another Inca bridge to the west of Machu Picchu, the tree-trunk bridge, at a location where there is a gap between the cliffs that measure 6 meter (20 feet), could be bridged by two tree trunks. If the trees were removed, it would leave a 570 meter (1,900 feet) fall to the base of the cliffs, also discouraging invaders.

The city sits in a saddle between the two mountains Machu Picchu and Huayna Picchu, with a commanding view down two valleys and a nearly impassable mountain at its back. It has a water supply from springs that cannot be blocked easily, and enough land to grow food for about four times as many people as ever lived there. The hillsides leading to it have been terraced, not only to provide more farmland to grow crops, but to steepen the slopes which invaders would have to ascend. The terraces also helped reduce soil erosion and protects against landslides. There are two high-altitude routes from Machu Picchu across the mountains back to Cusco, one through the sun gate, and the other across the Inca bridge.

Peru - Cusco