For the time period 900 to 1200 AD, Vikings, by nearly all accounts, ruled the northern Atlantic. Their skill in building strong boats and in navigation allowed them to travel throughout the North Atlantic. Prior research has suggested the Vikings used a type of sundial to navigate, which was apparently quite accurate. But what did they do when it was cloudy or foggy? Viking tales passed down through the generations claimed it was through the use of sunstones, which allowed Viking navigators to find the sun even on