Welcome to Cahokia, a Pre-Columbian Native American city, the largest and most influential urban development of the Mississippian culture. Today, the Cahokia Mounds State Historic Site resides in St. Clair County, Illinois and is one of 24 UNESCO World Heritage Sites in the United States. The mounds are the largest prehistoric earthen structures in the Americas north of Mexico. The original site contained 120 of these mounds, over 6 square miles. Monks Mound is the largest, rising 10 stories tall. Excavation revealed the evidence of a large building, possibly a temple or chief residence. There is a petition to change the name, as it represents Trappist monks who stayed there after Euroamericans settled in the area. Change.Org Sophisticated engineering has been displayed throughout the site, including a Grand Plaza that was expertly and deliberately leveled, and not just for flooding as originally thought, but for ceremonies, gatherings, and games. Rattlesnake Mound is referred to a