A secret Roman terror weapon was recently discovered in Scotland. Rarely used, these "whistling" sling bullets were part of psychological warfare designed to strike fear into the heart of the enemies.
A small collection of bullets with carefully drilled holes in them were discovered on a hill in Scotland. The bullets, believed to be about 1,800 years old, were deadly weapons in the hands of expert slingers who would shoot them into the enemy territory with the intention of terrorizing them with the shrill and piercing sounds the bullets made as they traveled above the enemy. The tiny holes, which were expertly drilled into the small bullets, were designed to allow the bullets to travel at high speeds through the air and make terrifying shrieking sound, speculated the archaeologists who unearthed them.