In short
Around 3000 BCE, Indigenous peoples in what is now Illinois began constructing Cahokia Mounds, an ancient ceremonial and residential complex near present-day St. Louis. Over centuries, this site grew into one of North America's largest pre-Columbian settlements, with dozens of earthen mounds serving religious, political, and astronomical functions.
How it unfolded.
The five-minute version
What actually happened.
The Cahokia Mounds is the site of a Native American city directly across the Mississippi River from present-day St. Louis. The state archaeology park lies in south-western Illinois between East St. Louis and Collinsville. The park covers 2,200 acres (890 ha), or about 3.5 square miles (9 km2), and contains about 80 manmade mounds, but the ancient city was much larger. At its apex around 1100 CE, the city covered about 6 square miles (16 km2), included about 120 earthworks in a wide range of sizes, shapes, and functions, and had a population of between 15,000 and 20,000 people.
As it was happening
7 voices, 712223 days.
One beat at a time. Click any dot on the timeline to jump, press play for autoplay, or use the arrow keys to step.
Peak of Mississippian settlement
Cahokia reaches its maximum population and influence, with a complex urban layout including residential areas, plazas, and ceremonial structures organized around Monks Mound.
Voices from this moment (1)
Peak of Mississippian settlement
Jan 1
“Cahokia reaches its maximum population and influence, with…”
As it was happening
7 voices, 712223 days.
Day 0 · January 1, 1050
Peak of Mississippian settlement
Cahokia reaches its maximum population and influence, with a complex urban layout including residential areas, plazas, and ceremonial structures organized around Monks Mound.
“Cahokia reaches its maximum population and influence, with…”
- Peak of Mississippian settlement, Jan 1
Day 54786 · January 1, 1200
Gradual decline begins
Population at Cahokia begins to decline, possibly due to resource depletion, climate change, or social upheaval. The reasons remain debated among archaeologists.
“Population at Cahokia begins to decline, possibly due to…”
- Gradual decline begins, Jan 1
Day 127835 · January 1, 1400
Settlement abandonment
Cahokia is largely abandoned, though smaller populations may have remained in the region for centuries afterward.
“Cahokia is largely abandoned, though smaller populations…”
- Settlement abandonment, Jan 1
Day 278298 · December 16, 1811
New Madrid earthquake impacts region
A major earthquake in the New Madrid Seismic Zone affects the Mississippi River valley, altering the landscape where Cahokia once stood.
“A major earthquake in the New Madrid Seismic Zone affects…”
- New Madrid earthquake impacts region, Dec 16
Day 319587 · January 1, 1925
State archaeology park established
Illinois establishes the Cahokia Mounds State Historic Site to preserve and study the remaining mounds.
“Illinois establishes the Cahokia Mounds State Historic Site…”
- State archaeology park established, Jan 1
Day 340406 · January 1, 1982
UNESCO World Heritage Site designation
Cahokia Mounds is designated a UNESCO World Heritage Site, recognizing its international archaeological and cultural significance.
“Cahokia Mounds is designated a UNESCO World Heritage Site,…”
- UNESCO World Heritage Site designation, Jan 1
Day 712223 · January 1, 3000
Cahokia Mounds construction begins
Indigenous peoples begin constructing earthen mounds in the Mississippi River bottomlands, establishing what would become the largest pre-Columbian settlement north of Mexico.
“Indigenous peoples begin constructing earthen mounds in the…”
- Cahokia Mounds construction begins, Jan 1
The numbers.
6 numbers that anchor the scale.
By the numbers
The countable parts.
Approximate construction start
0 BCE
Primary mound height
0 feet (Monks Mound)
Total mounds remaining
0 mounds
State archaeology park size
0 acres
Peak population estimate
0–20,000 residents
Estimated peak occupation
0–1200 CE
The visual record.
Captured in time.
Captured before it changed
The web as it looked, the day it happened.
Wayback Machine snapshots of the pages people actually loaded that day. Click any card to open the archive at full size.
Sources & citations.
Sources
Where this came from.
Every claim on this page traces to a public, license-clean source. We don't asterisk well.
Wikipedia
1 source- 1.Cahokia Mounds
en.wikipedia.org