The Driftless Area is rich with unique archaeological discoveries. Massive earthen effigy mounds, burial mounds constructed in the shapes of animals, are concentrated on the high bluffs overlooking Driftless Area rivers, including the Mississippi and Wisconsin. Such effigy mounds, found predominantly in Wisconsin and Iowa, with a few specimens as far away as Ohio, are unique in all the world. Effigy mounds were constructed over a period of about 400 years until they suddenly and mysteriously stopped about 1050 AD.
Native Americans also left behind extensive ancient cave paintings and rock carvings, which have been documented by the Mississippi Valley Archaeology Center and others. Even a stone carving of a human head was found in a cave along the Wisconsin River.