Squatting is the action of occupying an abandoned or unoccupied area of land or a building, usually residential, that the squatter does not own, rent or otherwise have lawful permission to use. The United Nations estimated in 2003 that there were one billion slum residents and squatters globally. Squatting occurs worldwide and tends to occur when people who are poor and homeless find empty buildings or land to occupy for housing. It has a long history, broken down by country below.