They glide down darkened halls and staircases. They rattle around abandoned prisons. They pop up in front of loved ones with mysterious messages. You'd think eternal rest would appeal more than haunting some old castle, but ghosts just can't seem to move on. Why do ghosts do what they do? And why are we fascinated enough to include ghosts in plays, novels, movies, and TV shows? Learn more about the history and pop culture surrounding these spooky creatures.