Global Urbanization and City Structures

Posted on Feb 4, 2026 in Geography

Historical Development of Cities

Cities in Antiquity

  • Around 7,000 years ago, the first cities emerged in China, India, and the Middle East.
  • Structure centered around a palace, market, and temple, often protected by a defense wall.

The Greek Polis

  • The Greek city-state (*polis*) featured two main urban areas:
    • The **Acropolis**: The high, fortified area.
    • The **Agora**: The public square and marketplace.
  • By the 5th century BCE, the grid plan became common.

Roman Cities

  • Characterized by a regular, planned layout centered around the **Forum** (public square).
  • Structured by two main intersecting roads: the *Cardo* (North-South) and the *Decumanus* (East-West).
  • Advanced public facilities included pipes, paved roads, and sewers.

Cities in the Middle Ages

Islamic Cities

  • Featured an irregular plan with narrow, winding streets.
  • The **Medina** was the walled central city containing the main religious and administrative buildings.
  • Commercial neighborhoods developed around the Medina.

Christian Cities

  • Developed starting in the 12th century.
  • Typically walled and irregular in layout.
  • The central part of the city was dominated by the Church.

Cities in the Modern Age (15th–18th Centuries)

  • European cities experienced significant growth.
  • Geometric forms dominated urban planning, emphasizing rational distribution.
  • Fortifications evolved and adapted.

Industrial Cities (18th–19th Centuries)

  • Driven by the Industrial Revolution in Europe and North America.
  • Major cities experienced rapid, unplanned growth.
  • **Working-class neighborhoods** lacked planning and basic facilities, leading to bad hygiene and overcrowding.
  • Defense walls were often demolished to allow for expansion and restructuring.
  • The **Bourgeoisie** established new, planned residential neighborhoods.

Modern Cities (20th Century)

  • The industrial model of urbanization spread globally.
  • Rapid population increase led to challenges: pollution, traffic congestion, and housing shortages.
  • The development of **satellite cities** aimed to alleviate pressure on central areas.

Typology of Urban Centers

Metropolises by Global Influence

  • **World Metropolises**: Major cities whose activity has worldwide repercussions. They are highly populated and influence other countries.
  • **National Metropolises**: Typically the state or country capitals.
  • **Regional Metropolises**: Centers where communications and main services converge for a specific region.
  • **Small-Medium Sized Cities**: Influence the surrounding towns and often serve as provincial capitals.

Urban Networks

Regular Urban Network

  • Cities are evenly distributed and territories are well-connected.
  • Facilitates fluid exchange.
  • Often includes national and international metropolises.

Concentrated Urban Network

  • Development is clustered around a major metropolis.
  • While often balanced in developed countries, national services tend to be concentrated in the big city.

Forms of Urban Agglomeration

  • **Metropolitan Area**: A large city (metropolis) and the surrounding towns connected to it.
  • **Conurbation**: The result of two or more cities merging together physically, where each city maintains administrative independence.
  • **Megalopolis**: A vast urban area extending beyond the regional level, formed when different metropolitan areas and conurbations merge.

Urban Structure and Dynamics

Urbanization largely began in the 19th century. Nowadays, big cities often experience slow growth, while medium-sized cities show increasing population rates.

The City’s Center

  • **Old Town**: The historical core of the city.
  • **Central Business District (CBD)**: Characterized by modern skyscrapers and high population density during working hours. It serves as the economic and financial center.
  • **Residential Neighborhoods**: Includes *ensanches* (planned extensions) or newly built areas, typically featuring medium-height buildings.

Outskirts and Peri-Urban Areas

  • **Industrial States**: Factory complexes often located alongside major transport routes, adjacent to working-class neighborhoods.
  • **Shopping Centers**: Large areas dedicated to selling goods, usually situated alongside major roads for easier accessibility.
  • **Residential Suburbs**: Neighborhoods connected to the center by major roads, housing different economic and social groups:
    • The economic elite often reside in single-family houses or low-block developments.
    • Working-class housing is typically of lower quality and medium height.

Cities in Developing Countries

Urbanization has accelerated rapidly, resulting in a massive migration of the rural population to cities.

Characteristics of Developing World Cities

  • They concentrate large urban agglomerations that centralize nearly all economic and social activities.
  • Exhibit strong contrasts between the social elite and vast slum areas.
  • Suffer from significant housing deficits and inadequate public services.

The Urban Experience: Pros and Cons

Advantages of Urban Life

  • Access to extensive educational and cultural activities, and specialized study opportunities.
  • Centers of trade offering greater variety of goods and services.
  • Healthcare is generally more accessible.
  • Extensive labor market provides more job offers.
  • Wide range of leisure options.
  • Facilitates the merging of ideas and combination of cultures.

Disadvantages of Urban Life

  • Requires enormous amounts of water and energy resources.
  • Generates large volumes of solid and wastewater.
  • Frequent traffic jams and related transportation problems.
  • High levels of pollution and smog.
  • High living prices, often leading to depressed areas with few facilities.