Here: Concentric stone circles near rocks weighing more than a ton – apparently aligned to mark solar events – are believed to be part of a Paleo-Indian site in the Blue Ridge Mountains of Clarke County that an expert has dated to about 10,000 B.C. The complex along Spout Run has 15 above-ground stone features. Though still under study, it could be one of the oldest man-made structures in North America still in existence and twice as old as England’s Stonehenge. More. Follow UD News at Twitter! See also: The Science Fictions series at your fingertips (human evolution)