Project is informed by the study of a unique site: Cahokia Mounds. At the time, Cohokia covered more than six square miles. Today, Cahokia Mounds is considered the largest and most complex archaeological site north of the great pre-Columbian cities in Mexico. It included a central plaza, residential neighborhoods, more than 100 massive earth mounds and the wood henge. The Cahokia Woodhenge was a series of large timber. Annual equinox and solstice sunrise observation events are held at the site.