It’s a puzzle that might have enticed Indiana Jones. Let’s say there was a metropolis from ancient times hidden in North America. Where would it be?

This city was bigger than Paris or London at the time it existed, and it housed approximately 30,000 people. That’s about the size of Juneau Alaska today (if you include the surrounding boroughs). If this estimate is correct, it was the largest city in the United States until the 1780s, when the population of Philadelphia finally surpassed it. So where was this lost historic capital?

The city was called Cahokia. It hit its peak population in the year 1050, and then it was abandoned by the year 1400. We don’t even know the name of the people who lived there. The city is named after the Cahokia tribe which lived in the area, but for the record, the Cahokia tribe claimed no connection with the city; it was the European explorers who named it.

The original inhabitants are a group known as Mississipians. They were amazing builders and craftspeople, and they had a significant influence on the surrounding areas – just check out the extent of the territory they have been reported to have impacted.

Cahokia
Map of the Southeastern Ceremonial Complex by Heironymous Rowe at English Wikipedia

Studies suggest that Cahokia was in fact the first melting pot in North America, drawing in people from surrounding areas (as much as one third of their population consisting of immigrants from other tribes and groups). These people could have migrated away after the decline of the city, meaning that the Cahokia tribe might not be the descendants of the city builders.

St. Louis from Monks Mound
Never trust an arch. View from Monks Mound. Image: mddscudder on Flickr

So again, where was this metropolis hiding? How do we know it even existed at all? I bet you wouldn’t guess it was buried under the suburbs of St. Louis, would you? If this city was right under our noses all this time, why are we only really exploring it now?

They paved paradise and put up a parking lot

Exploration of the area occurred sporadically, and earthen mounds don’t make for particularly exciting discoveries like gold or jewels. So, this lost city went the way of most—instead of preserving the shifting space, for monuments or museums, it was used for growing room as the population in the area expanded.

The growth of human civilization can be a bit unforgiving at times to ancient historical sites. Famous historical cities of the world are built on the ruins of their own past. Cahokia is no different.

Up goes a drive-in movie theatre here, a subdivision there, and a variety of other infrastructure required of our time. The area today is like any other in modern America, criss-crossed by roads and highways like veins in an ever-changing landscape, but underneath all of that it is filled with a rich history.

What was in the city?

While we have known about the ancient city for hundreds of years, our knowledge has largely been restricted to the awareness of mounds seen above the surface. Those mounds are pretty impressive though. Consider that all the mounds in Cahokia were built by hand. People dug up clay and transported it by hand, likely in woven baskets.

Monk’s Mound
Aerial view of Monk’s Mound via WesternDigs

One of the most notable mounds is the one called Monks Mound. Monks Mound rises 100 feet high (about 30 meters) and has three distinct levels. Archeological evidence shows that there was a building at the peak of the mound which could have risen another 50 feet (15 meters).

This mound is estimated to have taken as much as 250 years to build, but new evidence suggests it might have been completed in a mind-blowing 20 years. The entire structure was made up of an estimated 22 million cubic feet/623 thousand cubic meters of earth (that’s a lot of baskets).

To put the size of the mound into perspective, the base of the mound is comparable to the Great Pyramid at Giza, and it is the largest prehistoric earthen construction in America north of Mexico.

The Monks Mound
The Monks Mound. Image: Steve Moses on Flickr

Archeological studies suggest that the city is so much more than just mounds. There are extensive ceremonial areas, including at least one Woodhenge – a structure similar to Stonehenge in the UK, that was used to monitor the movement of the sun and stars to predict events such as harvests.

There are also extensive living areas, the grand plaza gathering area, a copper workshop, burial sites, and evidence of an extensive wooden palisade (estimated at 15 feet tall, or 4.6 meters). Over 1,000 years ago, this was a pretty happening place.

Cahokia
Illustration of Cahokia as it might have been.

Unfortunately, as the construction techniques in Cahokia involved using wood and earth, there are no stone ruins like we might see in Egypt or Rome. This means that the city was more easily reclaimed by nature—but that doesn’t make it any less impressive than its ancient counterparts.

Lessons from the past

If you’re thinking Cahokia sounds pretty amazing, you’re right. So, the obvious question is, why was it abandoned?

This is one of the most interesting questions about abandoned cities. In modern times the idea of abandoning a fully-formed city seems ludicrous (especially considering real estate prices in Toronto and Vancouver).

cahokia
Image: latinamericanstudies.org

New studies of the flood patterns of the Mississippi river might be shedding some light on the situation. The rise of Cahokia falls in line with periods of relatively low flooding. This would have made farming and city expansion relatively easy. Then, towards the end of the city’s life the floods returned, with one flood around the year 1200 being as much as 33 feet (10 meters) high. That’s the kind of stuff we make disaster movies about, so it is pretty easy to understand how that could contribute to the decline of the city.

cahokia
Image: latinamericanstudies.org

Flood researchers are also careful to say that there were likely a multitude of causes contributing to the decline of the city, such as war or disease. It boggles the mind in many ways. Think of our modern cities. What would it take for us to abandon New Orleans, New York, or another metropolis?

The whole area was designated as a state historical site about 40 years ago, and made a UNESCO World Heritage Site in 1982. It is always comforting to see history receive the recognition it so richly deserves, but this ancient metropolis also has a lesson for all of us in modern times: the greatest cities of mankind are often very dependent on specific environmental circumstances, and if those circumstances change they can have a very dramatic impact on the people who live in and around them.

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Alex Conde

Alex Conde is a writer and someone who is fascinated by this crazy world we live in. He believes we're surrounded by amazing stories (and a lot of interesting shit), and as a writer he has the pleasure of researching those stories and telling them so that other people can appreciate them as well.