MachuPicchu The lost city of the Inkas

"Machu Picchu is a late Inca town dramatically sited on the saddle between two mountains, Machu Picchu (Old Mountain) and Huayna Picchu (Young Mountain), overlooking the Urubamba River, which winds 3000 ft below it. Its buildings, all constructed of local stone, use various types of walling, from coursed ashlar to roughly dressed rubble, and incorporate characteristic trapezoidal doorways. Some of the walls have rectangular niches formed on the inner side. Masonry gables still stand and some buildings have trapezoidal window openings. The steep slopes of the site are terraced with masonry retaining walls to hold soil for the gardens, and the various levels of the town are linked by stone stairways."Sir Banister Fletcher. A History of Architecture. p688.