The tooth fairy is an example of Americanfolklore mythology. The fairy gives chilren a gift (often money) in exchange for a baby tooth when it comes out of the child's mouth. Children typically leave the tooth under their pillow for the fairy to take while they sleep. The tooth fairy then adds the tooth to a special part of her mythical and ever expanding all-white tooth castle in the sky. While originating in the United States, the tooth fairy myth is actively practiced in Ireland, Italy, South Africa, Australia, Canada, New Zealand and much of the UK.