Machu Picchu

is a city founded by the Incas high in the Peruvian Andes above the valley of the Río Urubamba. It was built in the 15th century and later abandoned. The site is famous for its ingenious dry stone walls, to which huge blocks of stone were piled without mortar. 
 

Characteristic of the fascinating buildings is their relational astronomical orientation and the panoramic view they offer. Their exact use remains a mystery.