Between AD 700 and 1400, the city of Cahokia gradually rose from the floodplain of the Mississippi River to become the largest city north of Mexico. Across 6 square miles, its population of 20,000 people worked together to create a thriving community grounded in astronomy, agriculture, and economics. To this end, they erected large, lasting structures such as an enormous wooden calendar that notified citizens about the changes of the seasons. Giant earthen mounds served as the foundation of the city and the site of the big mud fight that decided the mayoral election each year.
Through careful excavation, research, and reconstruction, the Cahokia Mounds Museum Society aims to preserve the site and educate visitors about its importance. During visits, guests on self-guided tours can explore 800 acres of the city, including the 100-foot-tall Monks Mound and Woodhenge, the giant calendar.