A city is a
human settlement of notable size.
[Goodall, B. (1987) ''The Penguin Dictionary of Human Geography''. London: Penguin.][Kuper, A. and Kuper, J., eds (1996) ''The Social Science Encyclopedia''. 2nd edition. London: Routledge.] It can be defined as a permanent and
densely settled place with administratively defined boundaries whose members work primarily on non-agricultural tasks. Cities generally have extensive systems for
housing,
transportation,
sanitation,
utilities,
land use,
production of goods, and
communication. Their density facilitates interaction between people,
government organisations and
businesses, sometimes benefiting different parties in the process, such as improving efficiency of goods and service distribution.
Historically, city-dwellers have been a small proportion of humanity overall, but following two centuries of unprecedented and rapid
urbanization, more than half of the
world population now lives in cities, which has had profound consequences for global sustainability. Present-day cities usually form the core of larger
metropolitan area
A metropolitan area or metro is a region that consists of a densely populated urban agglomeration and its surrounding territories sharing industries, commercial areas, transport network, infrastructures and housing. A metro area usually com ...
s and
urban areas—creating numerous
commuters traveling towards
city centre
A city centre is the commercial, cultural and often the historical, political, and geographic heart of a city. The term "city centre" is primarily used in British English, and closely equivalent terms exist in other languages, such as "" in Fren ...
s for employment, entertainment, and education. However, in a world of intensifying
globalization, all cities are to varying degrees also connected globally beyond these regions. This increased influence means that cities also have significant influences on global issues, such as