Urban Evolution: From Ancient Cities to Modern Megalopolises
Barcelona: Defining Urban Spaces
Defining areas inhabited by humans divides them into rural and urban areas. A city is a space with heterogeneous elements: natural, economic, and social. The criteria for distinguishing a city include the number of inhabitants, economic activity, and spatial organization. In Spain, a city is considered to have over 10,000 inhabitants, while in Japan it’s over 20,000, and in Sweden, 200.
Economic activity in cities primarily revolves around industry and services, unlike rural centers focused on primary activities. Urban spatial organization relates to the city and its surrounding territory.
Territorial Organization of Cities
Urban network distribution can be concentrated, regular, or random. Urban hierarchy distinguishes between:
- Urban Area: Core with a defined population.
- Central City: Administrative and physical hub for economic, political, and cultural activities.
- Metropolitan Area: Highly urbanized area with a central city and surrounding municipalities.
- Conurbation: Cities that have merged into a single urban area.
- Megalopolis: Large human concentration from the growth of cities, conurbations, and metropolitan areas (e.g., Randstad Holland in Europe).
The Industrial City
19th Century City
Districts called suburbs housed less privileged people. The Industrial Revolution led to new neighborhoods centered around factories and planned expansions. Improvements included sewer systems and transportation.
20th Century City
Expansions grew, industrial estates and residential areas emerged on city outskirts. Bedroom communities developed due to high demand. Conurbations, metropolitan areas, and megacities appeared globally, in both developed and developing countries.
Urban Planning
- Irregular Grid: Disordered streets, often near rivers or mountains, typical of ancient cities.
- Orthogonal Grid: Straight, intersecting streets.
- Linear: Planned, ordered buildings.
- Radiocentric: Streets radiate from a central point, often a plaza, with perpendicular streets.
Urban Landscape Worldwide
Urbanization is the percentage of a country’s population living in urban areas. It varies globally. Most industrialized countries have a high urbanization rate.
Northern European Cities
Urban structure reflects history, with growth over centuries. A historic center often surrounds a cathedral or old buildings. Streets are narrow, hindering vehicle traffic. Administrative activities are centered in municipal government headquarters. Suburbs grew outside city walls, initially for lower classes, then for the bourgeoisie. Industrial estates and residential areas developed later.
- Residential Areas: Two or three-story houses with gardens.
- Bedroom Neighborhoods: Uniform blocks of flats.
- Industrial Estates: Peripheral areas for industries.
U.S. and Australian Cities
Modern cities result from historical processes, many are planned. They began in the 18th and 19th centuries, lacking historic districts except for older areas like Boston and Santa Barbara. They sprawl over kilometers, with a Central Business District (CBD) for commercial and financial activities.