The Upper Paleolithic in Europe spans roughly 40,000 years, from about 50,000 to about 12,000 years ago.

During those forty millennia, tens of millions of human beings lived, died, and were buried, exposed, or otherwise disposed of according to the practices of their communities.

The vast majority left no physical trace that has survived to the present.

The processes that destroy organic material — decomposition, scavenging, soil chemistry, geological disturbance — are overwhelmingly effective.

Only a tiny fraction of the dead of any era leave bones that survive long enough to be found.

Of those bones that survive, only a fraction are in good enough condition to be analyzed scientifically.