The evidence is concrete and specific enough to be vividly imaginable, and the uncertainty about interpretation is genuine enough to create the kind of open question that people genuinely want to understand.

The story is not “we found evidence of cannibalism in ancient Scotland” — which would be a closed statement — or “we found evidence of skull worship in ancient Scotland” — which would be equally closed.

It is “we found evidence of something remarkable, and we’re not entirely sure what it means,” which is a story that invites the reader to think rather than simply to receive.

The location also contributes to the appeal.