“Cuzco, the Inca capital located more than 11,000 feet above sea level, had perhaps 60,000 residents. A dense network of roads, storehouses, and administrative centers stitched together this improbable high-altitude empire, which ran down the 2,000-mile-long spine of the Andes Mountains. A king claiming divine status ruled the empire through a bureaucracy of nobles. Like the Aztecs, the empire consisted of subordinate kingdoms that had been conquered by the Incas and tribute flowed from local centers of power to the imperial core.”