Squatting is the act 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. In 2004, there were an estimated one billion squatters around the world, mainly in much of the Global South, where extensive slums and shanty towns built on the edge of major cities built without permission. In the Global North, squatting is used by autonomists and anarchists to provide free housing and social centers to cities.