The Inka Empire, was the largest empire in pre-Columbian America, and possibly the largest empire in the world in the early 16th century. The administrative, political and military center of the empire was located in Cusco in modern-day Peru. The Inca civilization arose from the highlands of Peru sometime in the early 13th century. Its last stronghold was conquered by the Spanish in 1572.The Inca Empire was unique in that it lacked many features associated with civilization in the Old World. In the words of one scholar, "The Incas lacked the use of wheeled vehicles. They lacked animals to ride and draft animals that could pull wagons and plows...[They] lacked the knowledge of iron and steel...Above all, they lacked a system of writing...Despite these supposed handicaps, the Incas were still able to construct one of the greatest imperial states in human history".The Incan economy has been described as "feudal, slave, socialist.Since the Inca Empire lacked a written language, the main form of communication and recording in the empire were quipus, ceramics and spoken Quechua, the language the Incas imposed upon the peoples within the empire.Inca myths were transmitted orally until early Spanish colonists recorded them; however, some scholars claim that they were recorded on quipus, Andean knotted string records.The Incas made human sacrifices.