Indigenous Americans dragged, carried or floated 5-ton tree more than 100 miles to North America's largest city north of Mexico 900 years ago

An aerial view of a grassy field with trees and a mound in the center.

Around 900 years ago, Indigenous Americans at Cahokia — the largest pre-Columbian city north of Mexico until colonial times — felled a giant tree and transported it more than 110 miles (180 kilometers) to serve as a monumental marker post, a new study finds.

The tree, known as the Mitchell Log, is the largest marker post of its kind in Cahokia, which is now known for its earthen mounds in southwestern Illinois.