What causes a place to become haunted? No one really knows. In fact, there are so many types of hauntings from human ghosts, to animal ghosts, and even ghost ships, that no one has ever been able to come up with a general theory that can explain all of them. Any single theory would have to cover an immense variety of phenomena, and it just can’t be done. But, of course, the lack of a single, all-encompassing theory is no reason to give up on a search for answers.