The Great Serpent of America is a 1,348-foot long, 3-foot high prehistoric effigy mound on a plateau of the Serpent Mound crater in Ohio. It has been designated a National Historic Landmark by the US Department of Interior and is one of the most mysterious monuments in North America. It is the largest serpent effigy in the world and researchers have discovered unquestionable astronomical alignments that may push back the history of the monument back to 3,000 BC. All images are taken from Google Images for educational purposes only.