Cities have appeared in diverse cultures, e.g., among the Aztecs, Maya, and Inca and in China and India, Mesopotamia and Egypt, and ancient Greece and Rome (see city-state). In all these civilizations cities were the centers of internal change and development. From the decline of Rome the cities were in eclipse, and in Western Europe their role as centers of learning and the arts passed to the monasteries. The 11th cent. saw the resurgence of vigorous cities, first in Italy and then in northern Europe, due mainly to a revival of trade; by the 13th cent., with the decline of feudalism, the dynamic life of the Middle Ages was centered in the cities. This time marks the rise of the great modern cities, e.g., Milan, London, Paris, and the Hanseatic cities.
The giant modern city is a product of the Industrial Revolution, which introduced large-scale manufacturing. Sheer size aggravated existing problems of urban life; some of them, such as sanitation, utilities, and distribution, have been better solved than others, such as housing and transport. As urban life came to furnish more remunerative and varied employment opportunities, rural populations increasingly were attracted, and by the 20th cent. some nations were faced with shortages of agricultural workers.
Modern cities are often complex, with subcities within them, e.g., Newark, N.J., falls inside the New York metropolis. The word megalopolis is sometimes used to describe the great swath of communities stretching N and S of New York City from Boston to Washington, D.C. In Great Britain the term conurbation refers to a similar cluster of urban areas such as the one centered on London. There are similar complexes of cities in Asia, notably that of Wuhan in China.
Among movements to reform urban life, some aim at abolishing cities as known today; this is the tradition exemplified by William Blaker, Henry Thoreau, William Morris, and Eric Gill. There are also less radical designs, like rational city planning, the development of rapid transit to distant suburbs, and garden cities. There have been many reforms aimed at restoring community life for the rootless strangers so numerous in modern cities; such is a common function of settlement houses, community centers, and other philanthropic and cooperative enterprises.
See H. Pirenne, Medieval Cities (tr. 1925, repr. 1956); G. Glotz, The Greek City and Its Institutions (tr. 1929, repr. 1965); M. Weber, The City (tr. 1958); L. Mumford, The City in History (1961); J. Jacobs, The Economy of Cities (1969); S. Thernstrom and R. Sennett, ed., Nineteenth-Century Cities (1969); W. A. Robson and D. E. Regan, ed., Great Cities of the World (3d ed., 2 vol., 1972); P. Geddes, City Development (1973); J. Gottman, The Coming of the Transactional City (1983); D. Harvey, Consciousness and the Urban Experience (1985); W. Rybczynski, City Life: Urban Expectations in a New World (1995).
Large industrialized cities generally have advanced systems for sanitation, utilities, land usage, housing, and transportation and more. This close proximity greatly facilitates interaction between people and firms, benefiting both parties in the process. However, there is debate now whether the age of technology and instantaneous communication with the use of the Internet are making cities obsolete.
A big city, or metropolis, may have suburbs. Such cities are usually associated with metropolitan areas and urban sprawl, creating large amounts of business commuters. Once a city sprawls far enough to reach another city, this region can be deemed a conurbation or megalopolis.
According to Vere Gordon Childe, for a settlement to qualify as a city, it must have enough surplus of raw materials to support trade . Bairoch points out that, due to sparse population densities that would have persisted in pre-Neolithic, hunter-gatherer societies, the amount of land that would be required to produce enough food for subsistence and trade for a large population would make it impossible to control the flow of trade. To illustrate this point, Bairoch offers “Western Europe during the pre-Neolithic, [where] the density must have been less than 0.1 person per square kilometer”, as an example. Using this population density as a base for calculation, and allotting 10% of food towards surplus for trade and assuming that there is no farming taking place among the city dwellers, he calculates that “in order to maintain a city with a population of 1,000, and without taking the cost of transportation into account, an area of 100,000 square kilometers would have been required. When the cost of transportation is taken into account, the figure rises to 200,000 square kilometers..." . Bairoch noted that 200,000 square kilometers is roughly the size of Great Britain.
In her book “The Economy of Cities,” Jane Jacobs makes the controversial claim that city-formation preceded the birth of agriculture. Jacobs does not lend her theory to any strict definition of a city, but her account suggestively contrasts what could only be thought of as primitive city-like activity to the activity occurring in neighboring hunter-gatherer settlements.
To argue that cities came first, Jacobs offers a fictitious scenario where a valued natural resource leads to primitive economic activity that eventually creates conditions for the discovery of grain culture. Jacobs calls the imaginary city New Obsidian, where a stock of obsidian is controlled and traded with neighboring hunting groups. Those that do not control the stock demand the obsidian, so hunters travel great distances to barter what they have. Hunters value obsidian because “[o]bsidian makes the sharpest tools to be had" . Hunters arrive with live animals and produce, providing New Obsidian with food imports. When New Obsidians want goods that they do not have access to at their settlement, they take the obsidian as a currency to other settlements for trade. This basic economic activity turns the little city into a sort of “depot” where, in addition to exporting obsidian, a service of obtaining, handling and trading of goods that are brought in from elsewhere are made available for secondary customers. This activity brings more people to the center as jobs are created and goods are being traded. Among the goods traded are seeds of all different sorts and they are stored in unprecedented combinations. In various ways, some accidental, the seeds are sown, and the variation in yields among the different types of seeds are readily observed, more readily than they would in the wild. The seeds that yield the most grain are noticed and trading them begins to occur within the city. Owing to this local dealing, New Obsidians find that their grain yields are the best and for the first time “the selection becomes deliberate and conscious. The choices made now are purposeful, and they are made among various strains of already cultivated crosses, and their crosses, mutants and hybrids . The new way of producing food allows for food surplus and the surplus is offset by the population increase that results from an increase in labor that the new production method has created. The new source of food allows New Obsidian to switch its imports from mostly food, to mostly other materials that neighboring settlements are rich in, but could not barter with before. The craftsman that develop in New Obsidian make good use of the explosion of the new material imports and the work to be done increases rapidly along with the population as neighboring settlements are absorbed by the city activities.
The inputs depend on the length of the perimeter:
(2) , where I stands for the quantity of inputs. This equation shows that the perimeter is proportional to the length of a side.
So there are increasing returns to scale:
(3) . This equation (algebraically, combining (1) and (2)) shows that with twice the inputs, you produce quadruple the output.
Also, economies of scale:
(4) . This equation (combining (1) and (2)) shows that the same output requires less input. “Cities, then, economize on protection, and so protection against marauding barbarian armies is one reason why people have come together to live in cities…” .
Similarly, “Are Cities Dying?” by Edward L. Glaeser, delves into similar reasons for city formation: reduced transport costs for goods, people, and ideas. An interesting piece from Glaeser’s article is his argument about the benefits of proximity. He claims that if you double a city size, workers have a ten percent increase in earnings. Glaeser furthers his argument by logically stating that bigger cities don’t pay more for equal productivity in a smaller city, so it is reasonable then to assume that workers actually become more productive if you move them to a city twice the size than they initially worked in. However, the workers don’t really benefit from the ten percent wage increase because it is recycled back into the higher cost of living in a bigger city.
Modern city planning has seen many different schemes for how a city should look. The most commonly seen pattern is the grid, favoured by the Romans, almost a rule in parts of the Americas, and used for thousands of years in China. Derry was the first ever planned city in Ireland, begun in 1613, with the walls being completed five years later. The central diamond within a walled city with four gates was thought to be a good design for defence. The grid pattern chosen was widely copied in the colonies of British North America. However, the grid has been around for far longer than the British Empire. The Ancient Greeks often gave their colonies around the Mediterranean a grid plan. One of the best examples is the city of Priene. This city even had its different districts, much like modern city planning today. Fifteen centuries earlier the Indus Valley Civilization was using grids in such cities as Mohenjo-Daro. Grid plans were popular among planners in the 19th century; such plans were typical in the American West, in places such as Salt Lake City and San Francisco. Also in Medieval times we see a preference for linear planning. Good examples are the cities established in the south of France by various rulers and city expansions in old Dutch and Flemish cities.
Other forms may include a radial structure in which main roads converge on a central point, often the effect of successive growth over long time with concentric traces of town walls and citadels - recently supplemented by ring-roads that take traffic around the edge of a town. Many Dutch cities are structured this way: a central square surrounded by concentric canals. Every city expansion would imply a new circle (canals + town walls). In cities like Amsterdam and Haarlem, and elsewhere, such as in Moscow, this pattern is still clearly visible.
This categorisation is descriptive, and not all ancients cities fit into this well, but it is used as a general touchstone when considering ancient cities.
One characteristic that can be used to distinguish a small city from a large town is organized government. A town accomplishes common goals through informal agreements between neighbors or the leadership of a chief. A city has professional administrators, regulations, and some form of taxation (food and other necessities or means to trade for them) to feed the government workers. The governments may be based on heredity, religion, military power, work projects (such as canal building), food distribution, land ownership, agriculture, commerce, manufacturing, finance, or a combination of those. Societies that live in cities are often called civilizations. A city can also be defined as an absence of physical space between people and firms.
In the ancient Americas, early urban traditions developed in Mesoamerica and the Andes. Mesoamerica saw the rise of early urbanism in several cultural regions, including the Classic Maya, the Zapotec of Oaxaca, and Teotihuacan in central Mexico. Later cultures such as the Aztec drew on these earlier urban traditions. In the Andes, the first urban centers developed in the Chavin and Moche cultures, followed by major cities in the Huari, Chimu and Inca cultures.
This roster of early urban traditions is notable for its diversity. Excavations at early urban sites show that some cities were sparsely-populated political capitals, others were trade centers, and still other cities had a primarily religious focus. Some cities had large dense populations whereas others carried out urban activities in the realms of politics or religion without having large associated populations. Theories that attempt to explain ancient urbanism by a single factor such as economic benefit fail to capture the range of variation documented by archaeologists (Smith 2002). The growth of the population of ancient civilizations, the formation of ancient empires concentrating political power, and the growth in commerce and manufacturing led to ever greater capital cities and centres of commerce and industry, with Alexandria, Antioch and Seleucia of the Hellenistic civilization, Pataliputra (now Patna) in India, Chang'an (now Xi'an) in China, Carthage, ancient Rome, its eastern successor Constantinople (later Istanbul), and successive Chinese, Indian and Muslim capitals approaching or exceeding the half-million population level. It is estimated that ancient Rome had a population of about a million people by the end of the first century BC, after growing continually during the 3rd, 2nd, and 1st centuries BCE. And it is generally considered the largest city before 19th century London. Alexandria's population was also close to Rome's population at around the same time, the historian Rostovtzeff estimates a total population close to a million based on a census dated from 32 CE that counted 180,000 adult male citizens in Alexandria. Similar administrative, commercial, industrial and ceremonial centres emerged in other areas, most notably Baghdad, which to some urban historians, later became the first city to exceed a population of one million by the 8th century instead of Rome.
Agriculture was practiced in sub-Saharan Africa since the third millennium BCE. Because of this, cities were able to develop as centers of non-agricultural activity. Exactly when this first happened is still a topic of archeological and historical investigation. Western scholarship has tended to focus on cities in Europe and Mesopotamia, but emerging archeological evidence indicates that urbanization occurred south of the Sahara in well before the influence of Arab urban culture. The oldest sites documented thus far are from around 500 CE including Awdaghust, Kumbi-Saleh the ancient capital of Ghana, and Maranda a center located on a trade rout between Egypt and Gao.
Most towns remained far smaller places, so that in 1500 only some two dozen places in the world contained more than 100,000 inhabitants: as late as 1700 there were fewer than forty, a figure which would rise thereafter to 300 in 1900. A small city of the early modern period might contain as few as 10,000 inhabitants, a town far fewer still.citation needed
Waste and sewage are two major problems for cities, as is air pollution coming from various forms of combustion, including fireplaces, wood or coal-burning stoves, other heating systems, and internal combustion engines. The impact of cities on places elsewhere, be it hinterlands or places far away, is considered in the notion of city footprinting (ecological footprint). Other negative external effects include health consequences such as communicable diseases, crime, and high traffic and commuting times. Cities cause more interaction with more people than rural areas, thus a higher probability to contracting contagious diseases. However, many inventions such as inoculations, vaccines, and water filtration systems have also lowered health concerns. Crime is also a concern in the cities. Studies have shown that crime rates in cities are higher and the chance of punishment after getting caught is lower. In cases such as burglary, the higher concentration of people in cities create more items of higher value worth the risk of crime. The high concentration of people also makes using auto mobiles inconvenient and pedestrian traffic is more prominent in metropolitan areas than a rural or suburban one.
Cities also generate positive external effects. The close physical proximity facilitates knowledge spillovers, helping people and firms exchange information and generate new ideas. A thicker labor market allows for better skill matching between firms and individuals. Another positive external effect of cities comes from the diverse social opportunities created when people of different backgrounds are brought together. Larger cities typically offer a wider variety of social interests and activities, letting people of all backgrounds find something they can be involved in.
Cities may however also have a positive influence on the environment. UN Habitat stated in its reports that if these that city living can be the best solution for dealing with the rising population numbers (and thus still be a good approach on dealing with overpopulation). This is because cities concentrate human activity into one place, making the environmental damage on other places smaller. Letting the cities have a positive influence however, can only be achieved if urban planning is improved and if the city services are properly maintained.
In New Zealand, according to Statistics New Zealand (the government statistics agency), "A city [...] must have a minimum population of 50,000, be predominantly urban in character, be a distinct entity and a major centre of activity within the region.. For example Gisborne, purported to be the first city to see the sun, has a population of only 44,500 (2006) and is therefore administered by a district council, not a city council. At the other extreme, Auckland, although it is usually referred to as a single city, is actually four cities: Auckland City, Waitakere City, North Shore City, and Manukau City.
Main article List of cities in Norway
These formal distinctions may differentiate larger towns from smaller ones (such as status as a separate powiat, or the conferring of the title prezydent on the mayor rather than burmistrz), but none of these is universally recognized as equivalent to the English city/town distinction.
In Portugal an urban area is called "cidade" ou "vila". There is also a the notion of "Grande Área Metropolitana" and "Comunidade Urbana". In general, a "cidade" is a place with more than 8.000 electors (more or less 10.000 inhabitants) and at least half of the following services: hospital, pharmacy, fire department, theatre/cultural house, museum, library, hostel services, basic and secondary schools, public transport and gardens/urban parks. A cidade's coat of arms has five towers, while a vila's has only four. A Grande Área Metropolitana is a wide urban area with at least 350.000 inhabitants and is composed by at least 9 municipalities. A Comunidade Urbana must have more than 150.000 inhabitants. There are two main metropolitan areas - Lisbon (the capital), in the centre of the country and Porto in the North. Lisbon Metropolitan Area has a population that exceeds 3 million, being one of the most important western European cities. A city deeply connected with the sea, history, tourism and other services. Greater Metropolitan Area of Porto has over 2 million inhabitants developing a considerable part of the portuguese economy nowadays.
In the United Kingdom (UK), a city is a town which has been known as a city since time immemorial, or which has received city status by letters patent — which is normally granted on the basis of size, importance or royal connection (the traditional test was whether the town had a cathedral) to gain city status. For example the small town of Ripon was granted city status in 1836 to coincide with the creation of the Diocese of Ripon, but also in recognition of its long-standing role as a supplier of spurs to royalty. In the United Kingdom, when people talk about cities, they generally include the suburbs in that. Some cathedral cities, such as St David's in Wales and Wells in England, are quite small, and may not be known as cities in common parlance. Preston became England's newest city in the year 2002 to mark the Queen's jubilee, as did Newport in Wales, Stirling in Scotland, and Lisburn and Newry in Northern Ireland.
A Review of Scotland's Cities led to the Fair City of Perth, Scotland, losing city status. By both legal and traditional definition, a town may be of any size, but must contain a market place. A village must contain a church. A small village without a church is called a hamlet.
In some U.S. states, any incorporated town is also called a city. If a distinction is being made between towns and cities, exactly what that distinction is often depends on the context. The context will differ depending on whether the issue is the legal authority it possesses, the availability of shopping and entertainment, and the scope of the group of places under consideration. Intensifiers such as "small town" and "big city" are also common, though the flip side of each is rarely used.
Some states make a distinction between villages and other forms of municipalities. In some cases, villages combine with larger other communities to form larger towns; a well-known example of an urban village is New York City's famed Greenwich Village, which started as a quiet country settlement but was absorbed by the growing city. The word has often been co-opted by enterprising developers to make their projects sound welcoming and friendly.
In Illinois, cities must have a minimum population of 2,500 but in Nebraska, cities must have a minimum of only 800 residents. In Idaho, Oregon, Kansas, North Dakota, Minnesota, and Iowa, all incorporated municipalities are cities. In Ohio, a municipality automatically becomes a city if it has 5,000 residents counted in a federal census but it reverts to a village if its population drops below 5,000. In Nebraska, 5,000 residents is the minimum for a city of the first class while 800 is the minimum for a city of the second class.
In all the New England states, city status is conferred by the form of government, not population. Town government has a board of selectmen for the executive branch, and a town meeting for the legislative branch. New England cities, on the other hand, have a mayor for the executive, and a legislature referred to as either the city council or the board of aldermen.
In Virginia, all incorporated municipalities designated as cities are independent of the adjacent or surrounding county while a town is an incorporated municipality which remains a part of an adjacent or surrounding county. The largest incorporated municipalities by population are all cities, although some smaller cities have a smaller population than some towns. For example, the smallest city of Norton has a population of 3,904 and the largest town of Blacksburg has a population of 39,573. The other U.S. independent cities are Baltimore, Maryland; St. Louis, Missouri; and Carson City, Nevada.
In Pennsylvania any municipality with more than 10 persons can incorporate as a Borough. Any Township or Borough with at least 10,000 population can ask the legislature to charter as a city. In Pennsylvania a village is simply an unincorporated community within a township.
A global city, also known as a world city, is a prominent centre of trade, banking, finance, innovations, and markets. The term "global city", as opposed to megacity, was coined by Saskia Sassen in a seminal 1991 work. Whereas "megacity" refers to any city of enormous size, a global city is one of enormous power or influence. Global cities, according to Sassen, have more in common with each other than with other cities in their host nations. Examples of such cities include London, New York City, Paris and Tokyo. The notion of global cities is rooted in the concentration of power and capabilities within all cities. The city is seen as a container where skills and resources are concentrated: the better able a city is to concentrate its skills and resources, the more successful and powerful the city. This makes the city itself more powerful in the sense that it can influence what is happening around the world. Following this view of cities, it is possible to rank the world's cities hierarchically. Other global cities include Singapore which is a city-state, Chicago, Los Angeles, Frankfurt, Milan and Hong Kong which are all classed as "Alpha World Cities" and San Francisco, Sydney, Toronto, Zürich, Madrid, Sao Paulo, Mexico City, Brussels, Moscow and Seoul which are "Beta World Cities". A third tier containing Barcelona, Taipei, Lisbon, Osaka, Buenos Aires, Melbourne, Montreal, Manila, Rome, Washington, Berlin, and Santiago, among others is called "Gamma world cities" .
Critics of the notion point to the different realms of power. The term global city is heavily influenced by economic factors and, thus, may not account for places that are otherwise significant. For example, cities like Rome, Delhi, Mumbai, Istanbul, Mecca, Mashhad, Karbala, Karachi, Lahore, Jerusalem and Lisbon are powerful in religious and historical terms but would not be considered "global cities." Additionally, it has been questioned whether the city itself can be regarded as an actor.
In 1995, Kanter argued that successful cities can be identified by three elements: good thinkers (concepts), good makers (competence) or good traders (connections). The interplay of these three elements, Kanter argued, means that good cities are not planned but managed.
In the United States, United Kingdom and Ireland, the term "inner city" is sometimes used with the connotation of being an area, perhaps a ghetto, where people are less wealthy and where there is more crime. These connotations are less common in other Western countries, as deprived areas are located in varying parts of other Western cities. In fact, with the gentrification of some formerly run-down central city areas the reverse connotation can apply. In Australia, for example, the term "outer suburban" applied to a person implies a lack of sophistication. In Paris, the inner city is the richest part of the metropolitan area, where housing is the most expensive, and where elites and high-income individuals dwell. In the developing world, economic modernization brings poor newcomers from the countryside to build haphazardly at the edge of current settlement (see favelas, shacks and shanty towns).
The United States, in particular, has a culture of anti-urbanism that dates back to colonial times. The American City Beautiful architecture movement of the late 1800s was a reaction to perceived urban decay and sought to provide stately civic buildings and boulevards to inspire civic pride in the motley residents of the urban core. Modern anti-urban attitudes are to be found in America in the form of a planning profession that continues to develop land on a low-density suburban basis, where access to amenities, work and shopping is provided almost exclusively by car rather than on foot.
However, there is a growing movement in North America called "New Urbanism" that calls for a return to traditional city planning methods where mixed-use zoning allows people to walk from one type of land-use to another. The idea is that housing, shopping, office space, and leisure facilities are all provided within walking distance of each other, thus reducing the demand for road-space and also improving the efficiency and effectiveness of mass transit.