Sterkfontein Caves

This guide to the Sterkfontein Caves near Johannesburg follows scientist Ronald Clarke, who in 1994 pulled a box labeled monkey bones off a museum shelf and recognized four small ankle bones as something else entirely. It traces the search that sent his colleagues Stephen Motsumi and Nkwane Molefe into the Silberberg Grotto, and years spent freeing a skeleton from rock as hard as concrete, millimeter by millimeter. Best heard at the mouth of the grotto itself.