Machu Picchu is a 15th-century Inca citadel located in the Eastern Cordillera of southern Peru on a mountain ridge at 2,430 meters (7,970 ft). Often referred to as the "Lost City of the Incas", it is the most familiar icon of the Inca Empire. It is located in the Machupicchu District within the Urubamba Province above the Sacred Valley, which is 80 kilometers (50 mi) northwest of the city of Cusco. The Urubamba River flows past it, cutting through the Cordillera and creating a canyon with a subtropical mountain climate.

The Inca civilization had no written language and following the first encounter by the Spanish soldier Baltasar Ocampo, no Europeans are recorded to have visited the site from the late 16th century until the 19th century. As far as historical knowledge extends, there are no existing written records detailing the site during its period of active use. The leading theory is that Machu Picchu was a private city for Incan royalty. The names of the buildings, their supposed uses, and their inhabitants, are the product of modern archaeologists based on physical evidence, including tombs at the site. Machu Picchu was built in the classical Inca style, with polished dry-stone walls. Its three primary structures are the Temple of the Sun, the Temple of the Three Windows, and the Intihuatana.