There was no reason to suspect that a 40,000 to 50,000-year-old human remain would yield the genes of a « Third Man », an unknown cousin. All unfolded in southern Siberia following what appeared to be the relatively trivial discovery of a human finger bone in the Denisova Cave. While the vast area of western Eurasia was home to two actors, the Neanderthals and anatomically modern humans, a third human type was present in the Altai, whose similar technology and forms of symbolic expressions rendered them undetectable up until now. After these three human species crossed paths, only our direct biological ancestors survived.