According to the United Nations World Tourism Organisation (UNWTO), tourism entails the movement of people to countries or places outside their usual environment for personal or business/professional purposes. These people are called visitors. Generally speaking, a visitor is classified as a (same-)day visitor if their trip does not include an overnight stay and a tourist if it does include an overnight stay. The purpose of their trip can be for business, leisure or personal reasons, other than to be employed by a resident entity in the country or place visited.