It is a line on a map, defined by the Earth’s axial tilt — the specific latitude above which the sun does not set at the summer solstice and does not rise at the winter solstice.

It marks the boundary of the region where polar days and polar nights occur, where the seasonal extremes of light and dark reach their maximum.

For most of human history, the area above the Arctic Circle has been understood as a frontier — a limit beyond which ordinary human life becomes increasingly difficult and eventually impossible.

The assumption that this frontier was reached only recently in human prehistory, when climate improved after the Last Glacial Maximum, was embedded in the standard models of Arctic human prehistory.

Yana demonstrates that this assumption was wrong — that the frontier was reached much earlier, that the people who crossed it were fully capable of sustaining themselves in the environment they found beyond it, and that the children they raised above the Arctic Circle 31,000 years ago were not anomalies but participants in an established way of life.