The most famous effigy in the world, Serpent Mound State Memorial, is best visited early or late in the day, when shadows are deep. Site interpretation is much enhanced by the small museum, and by the old iron tower allowing visitors to get an overhead view of the sprawling creature. Most beautiful are the snake's spiraling tail, the 3 main coils (which some claim offer astronomical alignments), and the head (or egg, or eye, or the sun) which faces the summer solstice sunset during celebrations every June 21.

A large Adena-era mound has stood nearby since long before the Fort Ancient culture created the effigy in about AD 1100. A trail to the right near the neck leads down to the creek below, revealing how the serpent's designers seem to have mimicked the pronounced head-like formation of the cliff itself, and the undulating curves of the bluff behind it.