Caitlin Rankin, PhD, RPA

Dr. Caitlin Rankin’s research shows that a long-held theory about why an ancient civilization passed out of existence was wrong. Cahokia Mounds in southwestern Illinois was the site of the largest city in North America and at the pinnacle of its population in 1150, was larger than London or Paris. But over two centuries, its population waned.

Until Caitlin’s research findings found otherwise, a prevailing theory had been that residents of Cahokia caused the problem themselves; they caused the location to become uninhabitable because of poor environmental practices. But Caitlin’s examination of sediments on the site found evidence this wasn’t the case. “The people who lived in North America before the Europeans—they didn’t graze animals, and they didn’t intensively plow. We look at their agricultural system with this Western lens, when we need to consider Indigenous views and practices,” Rankin said in National Geographic magazine. (Article by Glenn Hodges, April 12, 2021).

Read her academic publication in the journal Geoarcheology. For a less-technical piece, read the article in the New York Times or this one from Washington University in St. Louis (the institution where Caitlin began this line of research when she was a graduate student.

Why not visit and see the site for yourself? Fly into St. Louis, which is only a half-hour from the historic site. Here’s some information. You could combine it with a longer trip to visit other ancient historic sites (including other mounds) in the Midwest; or make it part of a longer trip exploring the Mississippi River. In Illinois, Route 96 hugs the shores of this vast river valley for many miles. Hill prairies thrive on the bluffs.. (Late April and early May are a good time to visit to see spring ephemeral wildflowers, and any day in October is a good time for fall foliage.) 96 is one section of the Great River Road that stretches from Canada to the Gulf of Mexico.

Note from Jill: “During the interview, when I asked Dr. Rankin about other cities and comparisons of their sizes simultaneous to the period of thriving for Cahokia, she and I spoke about London and Paris. (Two examples of cities that existed concurrently and that were much smaller than Cahokia.) What she and I didn’t cover (because I didn’t get around to asking!) was that during that same period, there were cities on Earth that surpassed Cahokia in size. These included (but weren’t limited to) Constantinople, Baghdad, and Kaifeng.”