The Great Serpent Mound in Ohio is a prehistoric effigy mound that is 1,300 feet long and 3 feet high, making it the world’s largest surviving prehistoric effigy mound. It is situated on a plateau of a crater along Ohio Brush Creek in Adams County, Ohio. The mound has been controversial and mysterious for over a century. Despite extensive research, there has yet to be conclusive evidence of what it represents, when it was built, or its true purpose. However, it is believed that the Serpent Mound may have functioned as a type of calendar, as its various astronomical alignments suggest. Various interpretations of the Serpent Mound have been proposed, including that it represents a giant snake, moon phases, an eclipse, or the myth of the horned serpent found in many Native American cultures. Nevertheless, generations of researchers agree that the Serpent Mound holds astronomical significance, but the intent of those who built it and how it was used remains a mystery. https://www.ancient-origins.net/ancient-places-americas/serpent-mound-ohio-001594