The Rök stone is located in Ostergötland, in southern Sweden, and is the largest sign in the world: 2.5 visible meters and another hidden meter on the ground. The text of the ninth century is not complete and confuses several scriptures.

That is why it has not been possible to read clearly. So far it was thought that it was collecting heroic facts, but researchers from three Swedish universities have another interpretation: the Vikings feared the climate would cool. The climate disaster of the 6th century was stuck in the collective memory and three centuries later, after a solar storm, an eclipse and an atypical summer temperature, they believed that it would take colds again, hunger and deaths: Fimbulwinter, a sign of the end of the world in Nordic mythology.