Did the Vikings use crystal ‘sunstones’ to discover America?

Ancient records tell us that the intrepid Viking seafarers who discovered Iceland, Greenland and eventually North America navigated using landmarks, birds and whales, and little else. There’s little doubt that Viking sailors would also have used the positions of stars at night and the sun during the daytime, and archaeologists have discovered what appears to be a kind of Viking navigational sundial. But without magnetic compasses, like all ancient sailors they would have struggled to find their way once the clouds came over. —> Read More