I have blogged before about the extensive system of earthen mounds American Indian societies built in the Mississippi River region.
One example from Iowa is in the news.
“A team of archaeologists under the direction of the National Park Service is working to determine if some unauthorized construction damaged the Effigy Mounds National Monument in northeast Iowa.
The monument features over 200 mounds in the shape of bears and birds created by prehistoric American Indians over 1,000 years ago.
The team is looking to determine what, if any, damage was done by construction of a maintenance shed and an elevated boardwalk. Work was stopped a year ago when Park Service staff found the required paperwork hadn’t been completed.”