Built from an estimated 22 million cubic feet of earth and standing about 100 feet high, Monks Mound is the tallest structure at the Cahokia Mounds State Historic Site.

This American Indian metropolis was mysteriously abandoned. Archaeologists want to know why.

Cahokia was a robust economic and cultural center for the Mississippian people. They built hundreds of massive mounds but suddenly left the city in the 1300s.

Built from an estimated 22 million cubic feet of earth and standing about 100 feet high, Monks Mound is the tallest structure at the Cahokia Mounds State Historic Site.
Ira Block/National Geographic Image Collection
This content is Subscriber-Exclusive
You must have a National Geographic subscription to explore this article.

Read This Next

Is banning fishing bad for fishermen? Not in this marine reserve
SeaWorld allegedly violated the Animal Welfare Act. Why is it still open?
'World’s worst shipwreck' was bloodier than we thought

Go Further

Subscriber Exclusive Content

Why are people so dang obsessed with Mars?

How viruses shape our world

The era of greyhound racing in the U.S. is coming to an end

See how people have imagined life on Mars through history

See how NASA’s new Mars rover will explore the red planet

Why are people so dang obsessed with Mars?

How viruses shape our world

The era of greyhound racing in the U.S. is coming to an end

See how people have imagined life on Mars through history

See how NASA’s new Mars rover will explore the red planet

Why are people so dang obsessed with Mars?

How viruses shape our world

The era of greyhound racing in the U.S. is coming to an end

See how people have imagined life on Mars through history

See how NASA’s new Mars rover will explore the red planet