This is the 2,200-acre (3.5 square miles) site of a pre-Columbian Native American city located near Collinsville, Illinois.

This state historic site originally contained around 120 human-created earthen mounds. Today, nearly 80 mounds exist, including the massive Monks Mound which covers nearly 14-acres at the base, and stands 100-feet tall.

West of Monks Mound is Woodhenge. Archaeologists discovered this timber circle during an excavation. The placement of the posts marked solstices and equinoxes, simular to England's Stonehenge. 

Cahokia Museum and Interpretive Center provides visitors with educational experiences regarding the historic site.