Viking ring fort and settlement, the Shetland Islands, Jarlshof, Scotland. It has been described as "one of the most remarkable archaeological sites ever excavated in the British Isles". It contains remains dating from 2500 BC up to the 17th century AD.
Not exactly divination but very interesting! Researchers now believe they have found one of the sunstones used by Viking explorers to explore when the sun and stars weren't visible. Iceland spar is the name of the crystal and after several tests it seems to be an incredibly accurate navigational aid!
Viking Sunstone found in ship wreckage! Calcite crystals like Icelandic Spar create a double image, splitting light into two rays. If the crystal is held east-west, the double image becomes a single image and thus allows a sailor to locate the sun. The crystal's refractive qualities continue to be useful even in low light, on a cloudy day, or for a while after the sun has set.
During WWII, soldiers were known to take precious family photos (and Pinup Girl photos) and put them under clear grips on their 1911 pistols - called Sweetheart Grips.Sweetheart Grips | Stukas Over Stalingrad