text: Table of Contents
  Definition of city
  A city is a large human settlement usually with dense population and majority of its residents are occupied in non-rural and non-agricultural pursuits. A common way to distinguish a city from other human settlements is by its population size, its functions and symbolic status.
  Many human geographers and historians have argued that cities that we occupy or seen in the 1990sare the products of a long evolutionary process during which the settlement of 15000BC gradually evolved into complex cities of today. This view may seem very appealing, but has ignored some important dimensions of contemporary urbanization, which states that no two cities are the same, they may be broadly similar to some extent, but cities are quite different in landscapes, cultures, economies, societies and lifestyles.
  Recent developments in technology, ICTs, (information Communication Technologies) and rapid changing life-styles have significantly influenced the functions of the contemporary cities. For instance, there is today the 24 hours city, the internet, email, GSM, social media and websites etc. which has made it possible for e-shopping, e-commerce, e-education, e-government and e-banking etc. hence, cities are formed and shaped by diverse set of processes which are unique according to the individual city.
  Whats the difference between a city and a town?
  A city is usually more populated than a town, houses within a city are arranged in a very desirable manner, and it has many physical structures, while a town the other hand has more population than a village but lower than a city. However, the population of a city maybe over 100, 000 to 300,000 people depending on the country, while a large town could have a population of 20,000 to 100,000. In addition, a city could cover a wider area than a town and as it keeps expanding, it mayeven merge with surrounding areas. A town on theother hand, do not generally expand into other areas in the same way as cities.
  Some of the unique characters that define a city include
  - The city size and the nature of economy, example of such city is Abuja, the capital of Nigeria, Lagos and Jos.
  - The nature of the nation within which the city is located and the city position within the world. Example is USA, and Abuja etc.
  - The relationships or linkages between networks of cities.
  Classification of cities
  To classify cities means organizing the different characteristics into same group so that the like terms can easily be compared and understood. The consistent fact about cities is that they are constantly changing and no two cities are alike, they have their own origin, and they develop on their own with time, hence, classifying them and understanding the processes of urban change may be a problem to many people.
  A simple classification of the city centres into similar type helps to make contrasts between different groups of cities and make distinctions with specific types of cities. However, cities play different roles, occupy different positions and perform different functions in the world economy. In 1993, Savage and Warde classified cities into five (5) groups, which include-
  - Third world cities
  - Cities in socialists countries
  - Older (former)industrial cities
  - Global or world cities-
  - New industrial cities
  1. The third world cities- these cities fall under developing nations (examples are some cities in African, Asia and Latin America); these cities are referred to as third world because they do not align with the policies of either the U.S or the former Soviet Union. These cities are measured by tightly compact physical form and socio-economic roles, which were not rightly specialized. Constraints of distance produced a walking city. According to Gideon Sjoberg (1960), these cities where characterized by
  - Smallness in population and size
  - Technology were based on human and animal energy rather than inanimate power
  - Rigid class structure and little social mobility
  - Roles were prescriptive rather than permissive
  - Shanty towns and squatter settlements
  - The city centre dominated the entire city, as it was the hub of governmental, religious and commercial activities.
  - Social segregation were based on class, ethnicity, occupation and kinship
  - Land use was uniform and organic. Examples of third world cities in Africa include Kano, Sokoto, Bauchi, and Zaria in Nigeria.
  2. Cities in socialists countries– majority of socialist cities that were built in socialist countries were self-sustainable, they had friendly environment that used clean technologies mostly for used by the people, they had lots of pedestrian paths, parks, sports areas, museums and schools within walking distance. However, industrial facilities were built not only near existing cities but also in areas where only small rural communities had existed. In such cases, new urban settlements emerged near the industrial plants to accommodate the workers. Examples of such cities include Venezuela, Poland, Hungary, and Nowa Huta. These cities actually failed because they were built based on ideological imaginations and could not meet the real needs of people in terms of security, housing and food supply.
  3. Older (former) industrial cities-older or former Industrial cities were characterised by the loosing of spatial bounds.
  - The advent of efficient inter-urban transport and the transformation of economic and social roles freed the city from the constraints of size, distance and cost, and restrictions on specialisation.
  - Construction of railway raises significant differentiation in the network of cities and new towns
  - Large manufacturing centres were emerged, thus allowing migration from rural to city areas.
  - Cities during this period were dangerous places to live in, due to health problems resulting from contaminated water, air, and communicable diseases.
  - The physical form remained compact because intra-city movement in much later. One example of such cities is the New York City.
  4. Global or world cities– a global city, also calledworld city is a city that enjoys significant competitive advantages and that serves as a hub within a globalizedeconomic system; global cities were involved in large amounts of global business. The concept of global city comes from urban geography and the view thatglobalizationcan be understood as largely created, facilitated, and enacted in strategicgeographic localesaccording to a hierarchy of importance to the operation of the global system offinanceandtrade. According to Wikipedia these cities are characterised as-
  - High-quality educational institutions, including renowned universities, international student attendance and research facilities
  - Centres of media and communications forglobal networks
  - Centres of new ideas and innovation in business, economics, culture, and politics
  - The existence of financial headquarters, astock exchange, and major financial institutions
  - Domination of the trade and economy of a large surrounding area
  - Major manufacturing centres with port and container facilities
  - Dominance of the national region with great international significance. Example of such cities include London, Paris, Amsterdam, Houston, Tokyo, SydneyandNew York City
  5. New industrial cities– new industrial cities or modern cities sprung up after the full development of industrial capitalism in the core nations- of the late 18th-century world system. These cities experienced rapid population increase due to in-migration which were characterized by increasing industries and thus, became centres of population and production. These cities are marked by an increased valuation of knowledge, social and economic specialization; they experienced improvement in internal transport and movement since WW11. In addition, these cities are further characterized by-
  - Suburbanisation (urban sprawl)
  - Increase speed and mobility, which means the city size no more had a visible physical limit.
  - Economic restructuring, as industry becomes foot-loose and moves to cleaner locations outside the city or international (globalization effects)
  - Development of complex megapolis with numerous and complex polycentric ( cities within a city)
  - Changes in employment from manufacturing to service- knowledge based, information communication technologies (ICTs).
  - Complex problem of the city include inner city decline, decay and deprivation, also there are problems of ethnicity, minority, racism etc.
  - It has increased valuation of knowledge. Examples of industrial cities include- Japan, Brazil, Toronto, Bokaro in India, Lagos and Jos in Nigeria.