CHAMPAIGN, ILLINOIS—Thomas E. Emerson and Kristin M. Hedman of the Illinois State Archaeological Survey-Prairie Research Institute at the University of Illinois suggest that internal conflict between social, political, ethnic, and religious factions living at Cahokia may have been responsible for its collapse. They say that osteological evidence and information from isotopic analysis collected from human remains unearthed at the pre-Columbian city indicate that as many as one-third of the people living at Cahokia were immigrants. “There is no smoking gun if you want to pin Cahokia’s dissolution on environmental factors.…It makes more sense, given the heterogeneous population with differences in language, and social, religious, and political cultures to look to internal dissension at Cahokia as the underlying reason,” Emerson said in a press release. For more on Cahokia, go to "Mississippian Burning."