In 2021, ISAS tested a non-invasive technique called electromagnetic induction (EMI) on Mound 37 at Cahokia Mounds State Historic Site in Collinsville, Illinois. Using EMI, ISAS was able to detect the architecture of Mound 37 and confirm that the mound was circular in shape. Monks Mound, the largest Indigenous earthwork in the Americas rises prominently in the background. Images