13. Effigy Mounds National Monument (Iowa)
Effigy Mounds National Monument, located in northeastern Iowa along the Mississippi River, preserves over 200 prehistoric mounds built by Native American cultures between 450 BCE and 1300 CE. Among these, approximately 30 are effigy mounds shaped like animals, including bears and birds, reflecting the spiritual beliefs of ancient Woodland cultures. The largest bear-shaped mound, known as the Great Bear Mound, measures 137 feet (42 meters) in length and 3.5 feet (1 meter) in height. The monument offers visitors opportunities to explore these ancient structures and contemplate the meanings of the mounds and the people who built them. (nps.gov)
