Beneath the suburbs of East St.

Louis, Illinois, under the parking lots and strip malls and highway interchanges of the American Midwest, the remains of a city are still there.

It did not disappear completely.

Its bones were too large for that.

The earthen mounds it left behind — some of them taller than a ten-story building — were simply too massive to be removed, even after centuries of plowing, construction, and deliberate destruction of the smaller ones.

What survived is the physical evidence of something that most Americans were never taught existed: a planned urban center, built by Native people of the Mississippian culture, that by the year 1100 CE was one of the largest settlements in the entire world north of the great cities of Mexico.

Cahokia.

The name itself is borrowed from a later, unrelated people who lived in the area when French colonizers arrived in the seventeenth century.

The people who built the city did not call it that.

We do not know what they called it.

But we know, from the physical remains they left behind, the biological evidence preserved in the soil, and the artifacts that have been excavated across decades of archaeological work, that this place was genuinely extraordinary — a city of perhaps 10,000 to 20,000 people at its height, surrounded by an estimated 40,000 or more living in its immediate hinterland, connected to trade networks stretching from the Gulf of Mexico to the Great Lakes to the eastern seaboard.

At its peak in the eleventh and twelfth centuries, Cahokia may have been larger than the city of London was at the same period.

It was certainly larger than any European settlement in North America for the next several centuries after it was abandoned.

And the question of why it was built, how it was governed, why it declined, and why it was so thoroughly erased from the American historical memory that most people today have never heard of it is one of the most compelling archaeological stories of the Western Hemisphere.

The short answer to why Americans don’t know about it: a history was written that did not have room for it.

But the city was there.

The Mounds That Would Not Disappear

The first thing you notice, if you visit the Cahokia Mounds State Historic Site in southwestern Illinois today, is that the landscape is wrong for the Midwest.