a slum is a part of a city or a town where many poor people live. it is a place where people may not have basic needs, such as running water, electricity, toilets, telephones, etc. some of these people may also have social disadvantages, such as unemployment, no access to education, no access to health care, no municipal services, etc. there are slums in most of the big cities of developing countries and least developed countries (which are also labelled as the "third world"). they may not be called "slum", however; see shanty town.