City

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[[de:Gro�stadt]]

A city is an urban area, differentiated from a town by size, population density, importance, or legal status, and usually consisting of residential, industrial and business areas together with administrative functions which may relate to a wider geographical area.

A large percentage of a city's area is generally taken up by buildings, roads, and streets. Waterways, lakes or parks may be the only undeveloped areas within the city proper. In American English, at least, the central business district is called "downtown".

There is no one standard international definition of a city: the term may be used either for a municipality possessing city status, for an urban locality exceeding a given population size or possessing particular regional economic or administrative significance, or for an agglomeration combining a single such central place together with suburban and satellite areas.

The term is not appropriate for a cluster (conurbation) of distinct urban places or for a wider metropolitan area which may include more than one city acting as a focus for parts of the area.

Contents

Geography

The geographies of cities are diverse. Often cities will either be coastal and have a harbor or be situated near a river for economic reasons. river and ocean transport in bygone days were (and in most cases still are) cheaper and more efficient than road transport over long distances.

Older European cities which have not been extensively rebuilt tend to have city centers where the streets are jumbled together, often seemingly without a structural plan. This is a legacy of earlier unplanned development and the idea that a confusingly winding street layout would confuse invading armies. Today this is usually perceived by tourists to be quaint and picturesque.

Modern city planning has seen many different schemes for how a city should look. The most commonly seen pattern is the grid, almost a rule in the United States, and used for hundreds of years in China. Other forms may include a radial structure in which main roads converge on a central point.

History

Cities have a long history, although opinions vary on whether any particular ancient settlement can be considered to be a city. The first true cities are sometimes considered to be large settlements where the inhabitants were no longer simply farmers of the surrounding area, but began to take on specialised occupations.

By this definition, the first cities we know of were located in Mesopotamia, such as Ur, and along the Nile, the Indus Valley Civilisation and China. Before this time it was rare for settlements to reach significant size, although there were exceptions such as Jericho, [[�atalh�y�k]] and Mehrgarh.

The growth of ancient and medieval empires led to ever greater capital cities and seats of provincial administration, with Rome, its eastern successor Constantinople and successive Chinese and later Indian capitals approaching or exceeding the half-million population level. Similar large administrative and ceremonial centres emerged in other areas, though on a smaller scale.

During the European Middle Ages, a city was as much a political entity as a collection of houses. A city could often have its own legislature, and sometimes a city could be directly under the supervision of the monarch, circumventing local noblemen. City residence brought freedom from customary rural obligations to the lord: "Stadtluft macht frei" ("City air makes you free") was a saying in Germany.

In exceptional cases like Venice, Genoa or [[L�beck]], cities themselves became powerful states, sometimes taking surrounding areas under their control or establishing extensive maritime empires, though this could sometimes impede the later development of a wider national state and economy. Similar phenomena existed elsewhere, as in the case of Sakai, which enjoyed a considerable autonomy in late medieval Japan.

Most cities 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 fifty, 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.

While the city-states of the Mediterranean and Baltic languished from the 16th century, Europe's national capitals benefited from the growth of commerce following the emergence of an Atlantic economy fuelled by the silver of Peru. By the 18th century, London and Paris rivalled the more traditional imperial capitals of Beijing, Istanbul and Tokyo.

The growth of modern industry from the late 18th century onward led to 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. Today the world's population is about half urban, with millions still streaming annually into the growing cities of Asia, Africa and Latin America.

Environmental effects

Modern cities are known for creating their own microclimates. This is due to the large clustering of hard surfaces that heat up in sunlight and that channel rainwater into underground ducts. As a result, city weather is often windier and cloudier than the weather in the surrounding countryside. Conversely, because these effects make cities warmer (urban heat shield) than the surrounding area, tornadoes tend to go around cities. Additionally towns can cause significant downstream weather effects.

Garbage and sewage are two major problems for cities, as is air pollution coming from internal combustion engines (see public transport).

See also : Cities of the world, List of metropolitan areas by population, Megacity

References

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