Side A: One of North America’s most spectacular effigy mounds, Serpent Mound is a gigantic earthen sculpture representative of a snake. Built on a spur of rock overlooking Ohio Brush Creek around 1000 A.D. by the Fort Ancient culture, the earthwork was likely a place of ceremonies dedicated to a powerful serpent spirit. The site is located on the edge of a massive crater, possibly formed by the impact of a small asteroid around 300 million years ago. Frederic Ward Putnam studied Serpent Mound between 1886 and 1889. Due largely to his efforts, Serpent Mound became the first privately funded archaeological preserve in the United States.