ARGYLE — More mounds were built by ancient Native Americans in Wisconsin than in any other region of North America — between 15,000 and 20,000, at least 4,000 of which remain today. 

Most impressive are the effigy mounds, huge earthworks sculpted in the shapes of thunderbirds, water panthers, and other forms, not found anywhere else in the world in such concentrations. 

Robert A. Birmingham and Amy L. Rosebrough argue that effigy mound groups are cosmological maps that model belief systems and relations with the spirit world. The authors advocate for their preservation and emphasize that Native peoples consider the mounds sacred places.

Robert A. Birmingham is the author of Spirits of Earth: The Effigy Mound Landscape of Madison and the Four Lakes and the coauthor of Aztalan: Mysteries of an Ancient Indian Town. Now retired, he served as the state archaeologist of Wisconsin for many years.