For your files…
6 miles from St. Louis is Cahokia, an ancient civilization that was larger than medieval London or Paris or Rome. It includes pyramid structures 10 stories tall. Dates to 1000 AD, with a series of a dozen similar sites around the south east it is called the Mississippian society. Their trade routes extended across the United States. A great show on this is found on the Smithsonian channel – Secrets: America's Lost Pyramid.
https://youtu.be/AcbC7V5KC9o?si=4GGe56PADXzGs_b4
Originally posted in the Bizarre Magick Facebook group.