I’m not a believer in ghosts myself – I’ve certainly never thought I’ve seen one. Many people do believe in their existence though, and ghosts continue to be a popular topic in literature and cinema. Here are some intriguing theories about them.

1. Payback

In medieval times, it was believed that ghosts were souls condemned to purgatory. They had to spend a certain amount of time paying for their misdeeds in an appropriate way. An eye for an eye indeed! That might make people think more about what they do in life …