The vast adobe city of Chan Chan in Peru was the largest city in pre-Columbian America. The building material used was adobe brick, and the buildings were finished with mud frequently adorned with patterned relief arabesques. The centre of the city consists of several walled citadels which housed ceremonial rooms, burial chambers and temples. The city was built by the Chimu around 850 AD and lasted until its conquest by the Inca Empire in 1470 AD. It is estimated that around 30,000 people lived in the city of Chan Chan.