cities

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, Harappa and other cities on a grid pattern, using ancient principles described by Kautilya, and aligned with the compass points.Smith,
Earliest Cities
", in Gmelch & Zenner (2002). The ancient Greek city of Priene exemplifies a grid plan with specialized districts used across the Hellenistic Mediterranean.

Urban areas

Urban-type settlement extends far beyond the traditional boundaries of the city proper in a form of development sometimes described critically as urban sprawl. Decentralization and dispersal of city functions (commercial, industrial, residential, cultural, political) has transformed the very meaning of the term and has challenged geographers seeking to classify territories according to an urban-rural binary.

Metropolitan areas include suburbs and exurbs organized around the needs of commuters, and sometimes edge cities characterized by a degree of economic and political independence. (In the US these are grouped into metropolitan statistical areas for purposes of demography and marketing.) Some cities are now part of a continuous urban landscape called urban agglomeration, conurbation, or megalopolis (exemplified by the BosWash corridor of the Northeastern United States.)

History

The cities of Jericho, Aleppo, Faiyum, Yerevan, Athens, Damascus and Argos are among those laying claim to the longest continual inhabitation.

Cities, characterized by population density, symbolic function, and urban planning, have existed for thousands of years. In the conventional view, civilization and the city both followed from the development of agriculture, which enabled production of surplus food, and thus a social division of labour (with concomitant social stratification) and trade. Early cities often featured granaries, sometimes within a temple. A minority viewpoint considers that cities may have arisen without agriculture, due to alternative means of subsistence (fishing), to use as communal seasonal shelters, Fredy Perlman, ''Against His-Story, Against Leviathan'', Detroit: Black & Red, 1983; p. 16. to their value as bases for defensive and offensive military organization,Ashworth (1991), pp. 12–13. or to their inherent economic function. Cities played a crucial role in the establishment of political power over an area, and ancient leaders such as Alexander the Great founded and created them with zeal.

Ancient times

Jericho and Çatalhöyük, dated to the eighth millennium BC, are among the earliest proto-cities known to archaeologists. However, the Mesopotamian city of Uruk from the mid fourth millennium BC (ancient Iraq) is considered by some to be the first true City, with its name attributed to the Uruk period.

In the fourth and third millennium BC, complex civilizations flourished in the river valleys of Mesopotamia, India, China, and Egypt. Excavations in these areas have found the ruins of cities geared variously towards trade, politics, or religion. Some had large, dense populations, but others carried out urban activities in the realms of politics or religion without having large associated populations.

Among the early Old World cities, Mohenjo-daro of the Indus Valley civilization in present-day Pakistan, existing from about 2600 BC, was one of the largest, with a population of 50,000 or more and a sophisticated sanitation system. China's planned cities were constructed according to sacred principles to act as celestial microcosms.

The Ancient Egyptian cities known physically by archaeologists are not extensive. They include (known by their Arab names) El Lahun, a workers' town associated with the pyramid of Senusret II, and the religious city Amarna built by Akhenaten and abandoned. These sites appear planned in a highly regimented and stratified fashion, with a minimalistic grid of rooms for the workers and increasingly more elaborate housing available for higher classes.

In Mesopotamia, the civilization of Sumer, followed by Assyria and Babylon, gave rise to numerous cities, governed by kings and fostering multiple languages written in cuneiform. The Phoenician trading empire, flourishing around the turn of the first millennium BC, encompassed numerous cities extending from Tyre, Cydon, and Byblos to Carthage and Cádiz.

In the following centuries, independent city-states of Greece, especially Athens, developed the '' polis'', an association of male landowning citizens who collectively constituted the city. The agora, meaning "gathering place" or "assembly", was the center of athletic, artistic, spiritual and political life of the polis. Rome was the first city that surpassed one million inhabitants. Under the authority of its empire, Rome transformed and founded many cities ('' coloniae''), and with them brought its principles of urban architecture, design, and society.

In the ancient Americas, early urban traditions developed in the Andes and Mesoamerica. In the Andes, the first urban centers developed in the Norte Chico civilization, Chavin and Moche cultures, followed by major cities in the Huari, Chimu and Inca cultures. The Norte Chico civilization included as many as 30 major population centers in what is now the Norte Chico region of north-central coastal Peru. It is the oldest known civilization in the Americas, flourishing between the 30th and 18th centuries BC. Mesoamerica saw the rise of early urbanism in several cultural regions, beginning with the Olmec and spreading to the Preclassic Maya, the Zapotec of Oaxaca, and Teotihuacan in central Mexico. Later cultures such as the Aztec, Andean civilization, Mayan, Mississippians, and Pueblo peoples drew on these earlier urban traditions. Many of their ancient cities continue to be inhabited, including major metropolitan cities such as Mexico City, in the same location as Tenochtitlan; while ancient continuously inhabited Pueblos are near modern urban areas in New Mexico, such as Acoma Pueblo near the Albuquerque metropolitan area and Taos Pueblo near Taos; while others like Lima are located nearby ancient Peruvian sites such as Pachacamac.

Jenné-Jeno, located in present-day Mali and dating to the third century BC, lacked monumental architecture and a distinctive elite social class—but nevertheless had specialized production and relations with a hinterland. Pre-Arabic trade contacts probably existed between Jenné-Jeno and North Africa. Other early urban centers in sub-Saharan Africa, dated to around 500 AD, include Awdaghust, Kumbi-Saleh the ancient capital of Ghana, and Maranda a center located on a trade route between Egypt and Gao.

Middle Ages

In the remnants of the Roman Empire, cities of late antiquity gained independence but soon lost population and importance. The locus of power in the West shifted to Constantinople and to the ascendant Islamic civilization with its major cities Baghdad, Cairo, and Córdoba. From the 9th through the end of the 12th century, Constantinople, capital of the Eastern Roman Empire, was the largest and wealthiest city in Europe, with a population approaching 1 million. The Ottoman Empire gradually gained control over many cities in the Mediterranean area, including Constantinople in 1453.

In the Holy Roman Empire, beginning in the 12th century, free imperial cities such as Nuremberg, Strasbourg, Frankfurt, Basel, Zurich, Nijmegen became a privileged elite among towns having won self-governance from their local lord or having been granted self-governanace by the emperor and being placed under his immediate protection. By 1480, these cities, as far as still part of the empire, became part of the Imperial Estates governing the empire with the emperor through the Imperial Diet.

By the 13th and 14th centuries, some cities become powerful states, taking surrounding areas under their control or establishing extensive maritime empires. In Italy medieval communes developed into city-states including the Republic of Venice and the Republic of Genoa. In Northern Europe, cities including Lübeck and Bruges formed the Hanseatic League for collective defense and commerce. Their power was later challenged and eclipsed by the Dutch commercial cities of Ghent, Ypres, and Amsterdam. Similar phenomena existed elsewhere, as in the case of Sakai, which enjoyed a considerable autonomy in late medieval Japan.

In the first millennium AD, the Khmer capital of Angkor in Cambodia grew into the most extensive preindustrial settlement in the world by area,Evans ''et al.''
A comprehensive archaeological map of the world's largest preindustrial settlement complex at Angkor, Cambodia
, Proceedings of the National Academy of Sciences of the US, 23 August 2007.Map reveals ancient urban sprawl
", ''BBC News'', 14 August 2007. covering over 1,000 km² and possibly supporting up to one million people.

Early modern

In the West, nation-states became the dominant unit of political organization following the Peace of Westphalia in the seventeenth century. Western Europe's larger capitals (London and Paris) benefited from the growth of commerce following the emergence of an Atlantic trade. However, most towns remained small.

During the Spanish colonization of the Americas the old Roman city concept was extensively used. Cities were founded in the middle of the newly conquered territories, and were bound to several laws regarding administration, finances and urbanism.

Industrial age

The growth of modern industry from the late 18th century onward led to massive urbanization and the rise of new great cities, first in Europe and then in other regions, as new opportunities brought huge numbers of migrants from rural communities into urban areas. England led the way as London became the capital of a world empire and cities across the country grew in locations strategic for manufacturing. In the United States from 1860 to 1910, the introduction of railroads reduced transportation costs, and large manufacturing centers began to emerge, fueling migration from rural to city areas.

Industrialized cities became deadly places to live, due to health problems resulting from overcrowding, occupational hazards of industry, contaminated water and air, poor sanitation, and communicable diseases such as typhoid and cholera. Factories and slums emerged as regular features of the urban landscape.

Post-industrial age

In the second half of the twentieth century, deindustrialization (or " economic restructuring") in the West led to