The Moche civilization flourished in northern Peru from about 100 AD to 800 AD. Many scholars contend that the Moche were not politically organized as a monolithic empire or state. Rather, they were likely a group of autonomous polities that shared a common elite culture, as seen in the rich iconography and monumental architecture that survive today. They are particularly noted for their elaborately painted ceramics, gold work, monumental constructions, huacas and irrigation systems. Moche society was agriculturally based, with a significant level of investment in the construction of a network of irrigation canals for the diversion of river water to supply their crops. Their culture was sophisticated; and their artifacts express their lives, with detailed scenes of hunting, fishing, fighting, sacrifice, sexual encounters and elaborate ceremonies. The Moche cultural sphere is centered around several valleys on the north coast of Peru. Their Huaca del Sol, a pyramidal adobe structure on the Rio Moche, had been the largest pre-Columbian structure in Peru. However, it was partly destroyed when Spanish Conquistadores mined its graves for gold.