40,000-year-old adhesive used to repair tools found in a Berlin museum. Adhesive consists of ocher, a naturally occurring earth pigment, and bitumen, a hydrocarbon mixture.
With the right mixing ratio, the material is just sticky enough for a stone tool to get stuck in it, but your hands stay clean - a "sophisticated mixture" Neanderthals first used the Le Moustier cave around 120,000 years ago. About 40,000 year ago, the relatives of anatomically modern humans died out.