Sacsayhuamán, often spelled Sacsahuaman or Saqsaywaman, is a citadel on the northern outskirts of the city of Cusco, Peru, the historic capital of the Inca Empire. The site is at an altitude of 3,701 m. The complex was built by the Incas in the 15th century, particularly under Sapa Inca Pachacuti and his successors.