Live Science has a fascinating story about an ancient tree, which was part of Cahokia. Cahokia was the large city north of Mexico 900 years ago, with a population of around 20,000 people. It was built on earthen mounds in the southwestern Illinois, next to the Mississippi River, between East St. Louis and Collinsville. Scientists analyzed a large log, known as the “Mitchell Log”, was probably used as a monumental marker post. A new study published in the journal PLOS One has dated and located the source of the “Mitchell Log”.

“Cahokia grew rapidly in the late 11th century, with immigrants forming as much as a third of the population, before reaching its height in the mid-12th century when Cahokian goods, people, and ideas reached from the Gulf Coast up into the Great Plains,” study first author Nicholas Kessler, an assistant research professor at the Laboratory of Tree-Ring Research at the University of Arizona, and study co-author Erin Benson, an Eastern Woodlands archaeologist at the University of Illinois Urbana-Champaign, told Live Science in an email.

During this time, the Cahokians erected large monumental structures called marker posts. These posts were hewn from massive tree trunks and typically placed near communal courtyards, atop pyramid mounds and in prominent buildings.

“In the precontact Cahokian world, poles were often placed in special places (plazas, mounds, temples), where they acted as axis mundis, physically connecting the upper, middle, and under worlds and helping mediate those powers and people’s relationships with them,” Kessler and Benson said.