3. Serpent Mound (Ohio)
Serpent Mound, located in Adams County, Ohio, is a 1,348-foot-long (411-meter) prehistoric effigy mound constructed in the shape of a serpent. Its sinuous curves and coiled tail have sparked various interpretations regarding its purpose. Some scholars suggest it may have served as a ceremonial site, possibly related to astronomical events, as the head aligns with the summer solstice sunset. Others propose it was constructed by the Adena culture around 300 BCE, while more recent research indicates it was built by the Fort Ancient culture around 1070 CE. (history.com) Today, Serpent Mound is managed by the Ohio History Connection and is open to the public for exploration.
