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Serpent Mound
A quarter-mile earthen serpent in southern Ohio
Serpent Mound is the largest serpent effigy in the world, a low earthen embankment about 1,348 feet long that winds along a ridge above Ohio Brush Creek in Adams County, Ohio. Seen from above, the snake's body curves back and forth toward a tightly coiled tail, while at the other end its open jaws seem to hold an oval shape that some read as an egg, a sun or an eye. The mound stands only a few feet high, so its form is best seen from an observation tower.
Who built it, and when, is still debated. Radiocarbon studies have pointed both to the Adena culture, around 300 BCE, and to the later Fort Ancient culture, around 1070 CE, and archaeologists continue to argue over the evidence. Some researchers see an alignment between the serpent's head and the summer solstice sunset. Adding to the mystery, the mound sits on a rare geological feature, an ancient crater about 8 miles across, thought to have been made by an impact some 300 million years ago. Saved from plowing in the 1880s, it is now a National Historic Landmark.