Both left genetic traces in our genomes.

Both eventually disappeared — the Neanderthals approximately 40,000 years ago, the Denisovans at an unknown but similarly ancient date.

What was lost when these groups went extinct is not recoverable.

Not their languages, if they had them in the full sense.

Not their specific traditions of toolmaking, their ways of understanding the world, their social customs and rituals.

Not the particular knowledge they had accumulated about the landscapes they had inhabited for hundreds of thousands of years.

Denny is a reminder of that loss, made personal.