A city is an urban area with high population density which is dominated primarily industry and services. It differs from other urban institutions by various criteria, which include population, population density or legal status, although the distinction varies between countries. The population of a city can vary from a few hundred inhabitants to ten million. Cities are the most densely populated areas of the world; including Sao Paulo with its nearly 20 million people has a population density about 7,160 inhabitants per square kilometer, while all Brazil has more than 22 inhabitants / km ². The term is often used to designate city a particular political-administrative entity urbanized. In many cases, however, the word is also used to describe an area of development contiguous (which may include various administrative entities). For example, the city of London itself has only about 860 000 inhabitants. However, when someone refers to the city of London, usually refers to the metropolitan area, i.e. the set of built-up area, which has about 7.5 million people, another example is the Mexican city of Monterrey, Nuevo Leon, which has a metropolitan area composed of 11 municipalities, and major points of which are located throughout the metropolitan area, which is popularly known as Monterrey. Mexico City and its metropolitan area with over 20 million people is another example. could also be used as an example the confusion created when one speaks of Greater Buenos Aires, as the Greater Buenos Aires along with the Autonomous City of Buenos Aires are confused as one city, "Buenos Aires", but the Greater Buenos Aires is part of the province of Buenos Aires, Buenos Aires is the capital of the Republic of Argentina and are governed by different institutions, and the Autonomous City of Buenos Aires has capabilities of self-government almost identical to those of a province Argentina. Tokyo, often incorrectly described as a city, is actually a province of Japan, consisting of 23 different neighborhoods. The same applies to Santiago de Chile, which actually is not a city, because when it comes to it, people talk of the Province of Santiago, formed by 32 municipalities, the whole is generally called Greater Santiago.
The Conference European Statistics Prague proposed, without acceptance, regarded as agglomerations of cities over 10,000 inhabitants and 2,000 to 10,000 inhabitants provided the population engaged in agriculture should not exceed 25% of the total. From 10,000 inhabitants, all clusters are considered cities, where they are concentrated, usually in collective buildings in height, and are primarily engaged in activities of secondary and tertiary sectors (industry, trade and services). The political concept applies to city urban clusters institution capital and greater importance in the region and assumed the powers of the state or nation. It will be the capital city, but by extension the term applies to any administrative entity with some autonomy at the level of municipality, with the other names, like people, generic and ...