In folklore, a ghost is considered to be the spirit of a dead person or they are referred to as the supernatural by others. Scientists say that there are no real ghosts, but many people believe that there are. There a are huge amount of stories about ghosts in books and movies. Sometimes the ghost is the spirit of a person who was killed by someone or who was already dead. The ghost may stay on Earth because he or she has unfinished problems or is still trying to say goodbye to people who they missed. Sometimes ghosts are said to live in a particular locality, for example an abandoned house or a place that existed hundreds of years ago.