This city shows interesting technological achievements of the Maya civilization, such as a hydraulic sytem to solve the problem of flood ground. It is made up of administrative, residential and religious buildings on an approximate 25 sq. km area. The earliest signs of occupation date back to 400 b.C, and when the site reached its peak (from 400 to 1000 A.D.) there were around 25,000 inhabitants. After gradually declining, the site was abandonned in 1450.