For the John Templeton Foundation, I wrote about the spiritual and urban landscape of ancient Cahokia.
A little less than a thousand years ago, groups of Native Americans gathered near the Mississippi River in present-day Illinois to build a settlement of unprecedented size. “It’s an unusual phenomenon — a city in the middle of a continent without cities,” says Tim Pauketat, an archaeologist at the University of Illinois who has spent years studying the site, which was named in modern times for the unrelated Cahokia Indian tribe. According to the latest archaeological findings, Cahokia had three main precincts in an area of around 20 square kilometers, and at its peak was home to as many as 20,000 people. The countryside around the urban center was also heavily populated, with around 40,000 living within 40 kilometers of the city. The most obvious and lasting signs of the Cahokia’s civilization are the remains of more than 200 earthen mounds that served as platforms for many of the city’s buildings.
Because it lacked stone structures and much of its area has been heavily plowed by farmers in recent centuries, the true size of Cahokia and its outlying settlements had been difficult for archaeologists to gauge before modern surveying techniques like aerial LIDAR scans became available. Such surveys have turned up a number of outlying apparent religious sites built in careful alignment with Cahokia, and uncovered especially strong links between the urban center and an isolated earthwork site about 25 kilometers away that is known as the Emerald Mound. “The first Anglo Pioneers moving through the area reported an Indian road that went between Emerald Mound and Cahokia itself,” Pauketat says. That road — which modern digs show was a two-lane thoroughfare 50 meters wide and running in arrow-straight segments between the two sites — indicates that despite its relatively distant location, the Emerald site was of great importance to Cahokia’s residents. “The evidence really led us to wonder, what in the world is that thing sitting out in an area that doesn’t seem to be full of other human habitations?”