flood sediment

Monks Mound is the largest remaining mound at Cahokia, near Collinsville. Photo by Tim Vickers. Nearly 1,000 years ago, a bustling city sprouted in southern Illinois. As many as 20,000 people lived in this six-square-mile metropolis located near modern St. Louis around the year 1050, but then the civilization simply disappeared. Now, one team of […]