The Klasies River Caves are a series of caves located to the east of the Klasies River mouth. The three main caves and two shelters at the base of a high cliff have revealed evidence (20m of thick deposits) of middle stone age-associated human habitation from approximately 125 000 years ago.
Around 75 000 years ago during cave remodeling, the stratigraphic sediments were moved out into external middens. In 1998, the South African government submitted a proposal to add the caves to the list of World Heritage Sites.
From 1960 Ronald Singer, Ray Inskeep, John Wymer, Hilary Deacon, Richard Klein and others suggested the excavation yielded the earliest known remains of anatomically modern humans and behaviourally modern humans in the world. Further analysis
suggested that those specimens fall "outside the range of modern variation”.