15th-century Inca citadel in the Peruvian Andes, 2,430 m above sea level. Inscribed 1983. Built around 1450, abandoned a century later, unknown to the outside world until 1911.
From Wikipedia
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). It is situated in the Machupicchu District of Urubamba Province about 80 kilometers northwest of Cusco, above the Sacred Valley and along the Urubamba River, which forms a deep canyon with a subtropical mountain climate.