Machu Picchu is in Peru, high in the Andes above the Urubamba Valley.
The Inca built the citadel in the 15th century, probably during the reign of Pachacuti, an emperor who greatly expanded the Inca state. Its precisely fitted stonework, terraces, plazas, and drainage systems show sophisticated engineering in a difficult mountain environment.
Machu Picchu was probably a royal estate or ceremonial site rather than the ordinary capital of the Inca Empire. It was connected to the wider Inca road system and may have been abandoned during the Spanish conquest, although the Spanish do not appear to have recorded it directly.
The site became widely known internationally after Hiram Bingham publicized it in 1911. It is often called the “Lost City of the Incas,” but that nickname can mislead: local people knew of the ruins, and the major Inca capital was Cusco.