Making tracks next to Black Bear’s in the Bob Marshall Wilderness, Montana. What story would someone 100,000 years from now stitch together from our footprints? Somewhere between 112,000 and 121,000 years ago, a person walked along the muddy residue of a lake that today is so long gone it might be found only in myth. And maybe not even there—the oldest known story of humankind reaches back only 100,000 years.