Unless your history teacher was a real history buff or they had an affinity for the dark side of life your high school and college history courses probably left out most of the creepy bits.
They probably spoke about the Salem witch trials but chose not to touch on the fact that witch trials date back to the Middle Ages and beyond- and that animals were sometimes put on trial for witchcraft too.
History teachers may touch on the reign of Pope Gregory IX during the 13th century, and mention how he's the guy behind the Papal Inquisition, but they won't tell you how Gregory declared cats part of devil worship- and had them exterminated by the hundreds.
And even though history teachers will speak of Napoleon's defeat at Waterloo they hardly ever discuss the defeat Napoleon suffered eight years prior- at the paws of a horde of rabbits he was hunting.
See 25 Insanely Creepy Historical Facts They Never Taught You In School here