The genetic data extracted from it is stored in databases accessible to researchers around the world.

The paper describing its analysis has been cited hundreds of times and has changed the way scientists think about ancient human interactions.

A piece of bone smaller than a finger segment.

A child who lived for perhaps a decade or two before dying in the mountains of Siberia 90,000 years ago.

A genome that, by the accident of extraordinary preservation, survived long enough for the science to read it.

And in that genome, the story of two ancient human worlds coming together — briefly, intimately, productively — in the mountains at the edge of the world.