The Mystery of America’s Lost City

Imagine, in a time long before anyone could have written about it or photographed it, a bustling American city. Voices of different languages barter for well-crafted stone tools, clay pipes, and hundreds of other items in a crowded marketplace. Close by, some 1,000 spectators jam into the Grand Plaza—like a modern sports arena—to watch athletes compete.

And at the center of it all, on a massive hill made of earth, the community’s leaders look down, overseeing their people.

This place, known as Cahokia, existed a thousand years ago, in what is now Illinois. At its height, in about 1200 A.D., more than 20,000 people lived, worked, and played here along the banks of the Mississippi River.

But a little more than a century later, most of those people were gone. All that remains today is a mysterious grouping of grass-covered mounds rising above the plain.

Now archaeologists and historians are trying to solve the mystery of America’s very first city. Many questions remain: Who founded Cahokia? Why did they choose this spot for it? And perhaps most mysterious, why did they all suddenly leave?

Imagine long ago, a bustling American city. It is before anyone could have written about it or photographed it. People who spoke different languages could trade for well-crafted stone tools, clay pipes, and hundreds of other items in a crowded marketplace. Close by, 1,000 people crowded into the Grand Plaza—like a modern sports arena—to watch athletes compete.

A massive hill made of earth was in the center of it all. There the community’s leaders looked down, overseeing their people.

This place was known as Cahokia. It existed a thousand years ago, in what is now Illinois. In about 1200 A.D., more than 20,000 people lived, worked, and played here along the banks of the Mississippi River.

But a little more than a hundred years later, most of those people were gone. All that remains today is a mysterious grouping of grass-covered mounds rising above the plain.

Now archaeologists and historians are trying to solve the mystery of America’s very first city. Many questions remain. Who founded Cahokia? Why did they choose this spot for it? And perhaps most mysterious, why did they all suddenly leave?

Historians believe that small groups of Indigenous people started living in the grassy plain of southern Illinois around 8000 B.C. By around 700 A.D., a larger settlement began to take shape in one specific location, near the junction of the Mississippi, Missouri, and Illinois rivers. The settlement, which would become Cahokia, was important because of its fertile soil. Plentiful rain allowed settlers to grow bounties of corn and other crops. Living near rivers also fueled trade with other villages.

Historians believe that small groups of Indigenous people started living in the grassy plain of southern Illinois around 8000 B.C. By around 700 A.D., a larger settlement began to take shape in one specific location. It was near the junction of the Mississippi, Missouri, and Illinois rivers. The settlement would become Cahokia. It was important because of its rich soil. Plentiful rain allowed settlers to grow large amounts of corn and other crops. Living near rivers also helped make trade possible with other villages.

If you look at an aerial view of Cahokia today, you can still see the two things that sustained and defined it: rivers and mounds. The rivers—and the rain that fed them—spurred the city’s growth. The mounds are what history remembers as the face of Cahokia.

These earthen hills were far from the first of their kind. Indigenous people throughout the Americas first started building them around 5,000 years ago. But Cahokia had a lot of the mounds, about 120—and they were generally larger than those made before, say experts. Some of the mounds were used for burials of powerful leaders and some for ceremonial functions. People who had special status in the city—the religious or political elite—lived on the tops of others.

If you look at Cahokia today from above, you can still see the rivers and mounds that defined the city. The rivers and the rain helped the city’s growth. The mounds are what history remembers as the face of Cahokia.

These earthen hills were far from the first of their kind. Indigenous people throughout the Americas first started building them around 5,000 years ago. But Cahokia had a lot of the mounds. There were about 120 and they were generally larger than those made before, say experts. Some of the mounds were used for burials of powerful leaders. Others were used for ceremonial functions. Religious and political leaders lived on the tops of others.

Rising from the city’s center was the most important hill of all. Today called Monks Mound, it’s the largest structure ever erected out of earth in North America. Historians say it was built by hand out of more than 14 million baskets of soil. They believe tribal leaders probably ruled from a temple-like building at its top.

“There are many mounds built by others that came before [them],” says Belknap. “Of course, there is nothing in the U.S. that is close to Monks Mound, though.”

Rising from the city’s center was the most important hill of all. Today called Monks Mound, it’s the largest structure ever build out of earth in North America. Historians say it was built by hand out of more than 14 million baskets of soil. They believe tribal leaders probably ruled from a temple-like building at its top.

“There are many mounds built by others that came before [them],” says Belknap. “Of course, there is nothing in the U.S. that is close to Monks Mound, though.”

Yet despite Cahokia’s great pull, a strange thing happened: People began leaving. By the mid-1300s, historians say, the city was all but abandoned. No one knows exactly why. Some experts believe that the climate began to dry up, along with the ready stocks of corn. That may have prompted groups of people to move on, some to follow roaming buffalo herds as a source of food, clothing, and shelter.

According to Belknap, people likely left Cahokia for various reasons, including health and quality of life.

“Disease could also have played a role, as well as an unpopular leader,” she says.

As the people departed, they took their culture with them. Now known as Mississippian culture, it centered around growing corn and building platform mounds. Soon Cahokia’s influence had spread in all directions.

Then a strange thing happened. People began leaving Cahokia. By the mid-1300s, historians say, the city was all but abandoned. No one knows exactly why. Some experts believe that the climate began to dry up and less corn could be grown. This may have caused groups of people to move on. People began to follow roaming buffalo herds as a source of food, clothing, and shelter.

According to Belknap, people likely left Cahokia for various reasons, including health and quality of life.

“Disease could also have played a role, as well as an unpopular leader,” she says.

As the people left, they took their culture with them. It is now known as Mississippian culture. It centered on growing corn and building platform mounds. Soon Cahokia’s influence had spread in all directions.

Today Cahokia’s legacy lives on in modern people. Groups of Indigenous Americans, including the Osage in Oklahoma and the Omaha of Nebraska, trace their histories back to the great city.

Over the centuries, many of Cahokia’s mounds have been flattened for farms, roads, and homes. About 80 remain. The central section of the city is open to the public as the Cahokia Mounds State Historic Site. You can climb the 156 steps to the top of Monks Mound and behold the remains of earthen hills in the distance, as well as the deserted Grand Plaza, where so much life happened so long ago.

Some of the descendants of Cahokia are seeking more for the site: to turn it into a national park. There are two bills currently before Congress seeking that status.

Whatever happens, the area continues to have a spiritual connection for those who trace their roots there, says Osage archaeologist Andrea Hunter.

“It is a very powerful place, but it must be respected,” Hunter says. “Today’s generations are much more aware of this place as a sacred space.”

Today Cahokia’s legacy lives on in modern people. Groups of Indigenous Americans, including the Osage in Oklahoma and the Omaha of Nebraska, trace their histories back to the great city.

Over the centuries, many of Cahokia’s mounds have been flattened for farms, roads, and homes. About 80 remain. The central section of the city is open to the public as the Cahokia Mounds State Historic Site. You can climb the 156 steps to the top of Monks Mound. There you can see the remains of earthen hills in the distance, as well as the deserted Grand Plaza, where so much life happened so long ago.

Some of the descendants of Cahokia are seeking more for the site. They want to see it to turned it into a national park. There are two bills currently before Congress seeking that status.

Whatever happens, the area continues to have a spiritual connection for those who trace their roots there, says Osage archaeologist Andrea Hunter.

“It is a very powerful place, but it must be respected,” Hunter says. “Today’s generations are much more aware of this place as a sacred space.”