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. In developing countries and least developed countries, shanty towns often begin as squatted settlements. In African cities such as Lagos much of the population lives in slums. There are pavement dwellers in India and in Hong Kong as well as rooftop slums. Informal settlements in Latin America are known by names such as villa miseria (Argentina), pueblos jóvenes (Peru) and asentamientos irregulares (Guatemala, Uruguay). In Brazil, there are favelas in the major cities and land-based movements. In industrialized countries, there are often residential squats and also political squatting movements, which can be anarchist, autonomist or socialist in nature, for example in the self-managed social centres of Italy or squats in the United States. Oppositional movements from the 1960s and 1970s created freespaces in Denmark or squatting village in the Netherlands, and in England and Wales, there were estimated to be 50,000 squatters in the late 1970s. Each local situation determines the context: in Athens, Greece, there are refugee squats; Germany has social centres; in Spain there are many squats. Overview The majority of squatting is residential in nature. As a phenomenon it tends to occur when a poor and homeless population makes use of derelict property or land through urban homesteading. According to a 2003 estimate by the United Nations in the UN-Habitat report, there were about one billion people in squatter settlements and slums. According to an academic, Kesia Reeve, "squatting is largely absent from policy and academic debate and is rarely conceptualised, as a problem, as a symptom, or as a social or housing movement." In many of the world's poorer countries, there are extensive slums or shanty towns, typically built on the edges of major cities and consisting almost entirely of self-constructed housing built without the landowner's permission. While these settlements may in time become upgraded, they often start off as squats with minimal basic infrastructure. Thus, there is no legal link to sewerage, electricity or