City of David - King David's Palace IMG 5815.JPG

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 areas and urban areas—creating numerous commuters traveling towards city centres 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 sustainable development, global warming, and global health. Because of these major influences on global issues, the international community has prioritized investment in sustainable cities through Sustainable Development Goal 11. Due to the efficiency of transportation and the smaller land consumption, dense cities hold the potential to have a smaller ecological footprint per inhabitant than more sparsely populated areas. Therefore, compact cities are often referred to as a crucial element of fighting climate change. However, this concentration can also have significant negative consequences, such as forming urban heat islands, concentrating pollution, and stressing water supplies and other resources.

Other important traits of cities besides population include the capital status and relative continued occupation of the city. For example, country capitals such as Beijing, London, Mexico City, Moscow, Nairobi, New Delhi, Paris, Rome, Athens, Seoul, Singapore, Tokyo, Manila, and Washington, D.C. reflect the identity and apex of their respective nations. Some historic capitals, such as Kyoto and Xi'an, maintain their reflection of cultural identity even without modern capital status. Religious holy sites offer another example of capital status within a religion, Jerusalem, Mecca, Varanasi, Ayodhya, Haridwar and Prayagraj each hold significance.

Meaning

A city can be distinguished from other human settlements by its relatively great size, but also by its functions and its special symbolic status, which may be conferred by a central authority. The term can also refer either to the physical streets and buildings of the city or to the collection of people who dwell there, and can be used in a general sense to mean urban rather than rural territory.Kevin A. Lynch, "What Is the Form of a City, and How is It Made?"; in Marzluff et al. (2008), p. 678. "The city may be looked on as a story, a pattern of relations between human groups, a production and distribution space, a field of physical force, a set of linked decisions, or an arena of conflict. Values are embedded in these metaphors: historic continuity, stable equilibrium, productive efficiency, capable decision and management, maximum interaction, or the progress of political struggle. Certain actors become the decisive elements of transformation in each view: political leaders, families and ethnic groups, major investors, the technicians of transport, the decision elite, the revolutionary classes."

National censuses use a variety of definitions – invoking factors such as population, population density, number of dwellings, economic function, and infrastructure – to classify populations as urban. Typical working definitions for small-city populations start at around 100,000 people. Common population definitions for an urban area (city or town) range between 1,500 and 50,000 people, with most U.S. states using a minimum between 1,500 and 5,000 inhabitants. Some jurisdictions set no such minima. In the United Kingdom, city status is awarded by the Crown and then remains permanently. (Historically, the qualifying factor was the presence of a cathedral, resulting in some very small cities such as Wells, with a population 12,000 and St Davids, with a population of 1,841 .) According to the "functional definition", a city is not distinguished by size alone, but also by the role it plays within a larger political context. Cities serve as administrative, commercial, religious, and cultural hubs for their larger surrounding areas.Marshall (1989), pp. 14–15.

The presence of a literate elite is sometimes included in the definition. A typical city has professional administrators, regulations, and some form of taxation (food and other necessities or means to trade for them) to support the government workers. (This arrangement contrasts with the more typically horizontal relationships in a tribe or village accomplishing common goals through informal agreements between neighbors, or through leadership of a chief.) The governments may be based on heredity, religion, military power, work systems such as canal-building, food-distribution, land-ownership, agriculture, commerce, manufacturing, finance, or a combination of these. Societies that live in cities are often called civilizations.

The ''degree of urbanization'' is a modern metric to help define what comprises a city: "a population of at least 50,000 inhabitants in contiguous dense grid cells (>1,500 inhabitants per square kilometer)". This metric was "devised over years by the European Commission, OECD, World Bank and others, and endorsed in March 021by the United Nations... largely for the purpose of international statistical comparison".

Etymology

The word ''city'' and the related ''civilization'' come from the Latin root '' civitas'', originally meaning 'citizenship' or 'community member' and eventually coming to correspond with '' urbs'', meaning 'city' in a more physical sense."city, n.", ''Oxford English Dictionary'', June 2014. The Roman ''civitas'' was closely linked with the Greek ''polis''—another common root appearing in English words such as ''metropolis''.

In toponymic terminology, names of individual cities and towns are called ''astionyms'' (from Ancient Greek ἄστυ 'city or town' and ὄνομα 'name').

Geography

Urban geography deals both with cities in their larger context and with their internal structure. Cities are estimated to cover about 3% of the land surface of the Earth.

Site

Town siting has varied through history according to natural, technological, economic, and military contexts. Access to water has long been a major factor in city placement and growth, and despite exceptions enabled by the advent of rail transport in the nineteenth century, through the present most of the world's urban population lives near the coast or on a river.

Urban areas as a rule cannot produce their own food and therefore must develop some relationship with a hinterland which sustains them.Kaplan et al. (2004), pp. 155–156. Only in special cases such as mining towns which play a vital role in long-distance trade, are cities disconnected from the countryside which feeds them.Marshall (1989), p. 15. "The mutual interdependence of town and country has one consequence so obvious that it is easily overlooked: at the global scale, cities are generally confined to areas capable of supporting a permanent agricultural population. Moreover, within any area possessing a broadly uniform level of agricultural productivity, there is a rough but definite association between the density of the rural population and the average spacing of cities above any chosen minimum size." Thus, centrality within a productive region influences siting, as economic forces would in theory favor the creation of market places in optimal mutually reachable locations.

Center

The vast majority of cities have a central area containing buildings with special economic, political, and religious significance. Archaeologists refer to this area by the Greek term temenos or if fortified as a citadel. These spaces historically reflect and amplify the city's centrality and importance to its wider sphere of influence.Latham et al. (2009), p. 18. "From the simplest forms of exchange, when peasant farmers literally brought their produce from the fields into the densest point of interaction—giving us market towns—the significance of central places to surrounding territories began to be asserted. As cities grew in complexity, the major civic institutions, from seats of government to religious buildings, would also come to dominate these points of convergence. Large central squares or open spaces reflected the importance of collective gatherings in city life, such as Tiananmen Square in Beijing, the Zócalo in Mexico City, the Piazza Navonae in Rome and Trafalgar Square in London. Today cities have a city center or downtown, sometimes coincident with a central business district.

Public space

Cities typically have public spaces where anyone can go. These include privately owned spaces open to the public as well as forms of public land such as public domain and the commons. Western philosophy since the time of the Greek agora has considered physical public space as the substrate of the symbolic public sphere. Public art adorns (or disfigures) public spaces. Parks and other natural sites within cities provide residents with relief from the hardness and regularity of typical built environments.

Internal structure

Urban structure generally follows one or more basic patterns: geomorphic, radial, concentric, rectilinear, and curvilinear. Physical environment generally constrains the form in which a city is built. If located on a mountainside, urban structure may rely on terraces and winding roads. It may be adapted to its means of subsistence (e.g. agriculture or fishing). And it may be set up for optimal defense given the surrounding landscape. Beyond these "geomorphic" features, cities can develop internal patterns, due to natural growth or to city planning.

In a radial structure, main roads converge on a central point. This form could evolve from successive growth over a long time, with concentric traces of town walls and citadels marking older city boundaries. In more recent history, such forms were supplemented by ring roads moving traffic around the outskirts of a town. Dutch cities such as Amsterdam and Haarlem are structured as a central square surrounded by concentric canals marking every expansion. In cities such as Moscow, this pattern is still clearly visible.

A system of rectilinear city streets and land plots, known as the grid plan, has been used for millennia in Asia, Europe, and the Americas. The Indus Valley civilisation built Mohenjo-Daro