That began in Neolithic times, but throughout history we can distinguish two main stages:
PRE-INDUSTRIAL CITY Until the Industrial Revolution, no more than 10% of the population lived in cities, and they would normally not exceed 5,000 or 10,000. Their functions were military (control of territory), administrative (seat of political power), economic (market) and religious (temple). Three periods: classical, medieval and modern.
In the ninth and eighth centuries BC., Phoenicians and Greeks established trading posts along the coasts of Hispania, but the Romanization will be responsible for the beginning of the urbanization process.
The Roman plane copies that of the Greek Hipodamos of Miletus (grid or checkerboard), moving from the camps of the legions to the Roman colonies (Barcelona, Zaragoza, Merida, Italica ...).
Two North-South axis (Cardo) and East-West (Decumanus Maximus) cut the grid, in the crossroads there is a forum, to which we must add other public spaces (theater, amphitheater, baths, temples, circus ...). A wall surrounds the city (Lugo).
The Industrial Revolution will completely transform the cities from mid-nineteenth:
Textile and metallurgical factories attracted thousands of workers from the countryside.
The bourgeoisie abandoned the old town, unhealthy, uncomfortable, strangled by the walls, and constructed a new city (Ensanche). In the old town and in slums or shanty houses will be crowded the workers.
The new town will follow the plane grid, with wide spaces between buildings, gardens, wide streets and elegant homes, which connect the city with the railway station, the new transport system.
The division of the kingdom into provinces (1833) did also grow as new capitals cities where the industry came much later.
Urbanization was stronger during the 60s and 70s (development): development centers (polos de desarrollo), metropolitan areas, tourist towns ...
ALTOS HORNOS DE VIZCAYA ( blast furnaces ) FIRST TRAIN BARCELONA-MATARÓ
SHANTY HOUSES (CASAS MOLINERAS) IN VALLADOLID BARRI GÓTIC AND RAVAL IN BARCELONA
The extent of urban lifestyles and spaces occupied by the cities has brought to large urbanized areas, with different structure:
Metropolitan areas (Madrid, Barcelona, Bilbao, Valencia, Sevilla) organized around a large city with several satellite cities linked by a dense infrastructure network. The big city concentrates the more valuable tertiary and the area supports different uses of industrial, residential land or services.
Conurbation, or spatial union of cities with a similar size (east coast of Guipuzcoa, Costa del Sol, Algeciras Bay).
Urban area, diffuse conurbation in which cities fail to bind spatially (Central Asturias).
In well-integrated systems of cities, it is a constant relationship between the size of settlements and their rank. All settlements in a region are in descending order of population or size from the largest settlement. The second settlement is expected to be half the size of the first settlement, and the fifth largest settlement is a fifth of the first, as well with others.
Concave deviation: strong predominance of the larger settlement (the capital) for political or economic reasons: the Spanish case.
Convex deviation: poorly integrated system.
In our case, the second settlement (Barcelona) is much greater than that generally corresponds to the second city.
Is peripheral, despite the centrality of Madrid and its radial connections, partly because the inland demographic vacuum and the layout of the mountains.
Predominance of intermediate and small towns, no large conurbations (Bay of Cadiz and Algeciras, in central Asturias, Guipuzcoa coast, Costa del Sol), the largest are metropolitan areas (Madrid, Barcelona, Valencia, Seville, Bilbao, Malaga and Zaragoza).
No major inner axis around which to focus the nuclei, except the Ebro and the Guadalquivir. The highway of Castile is very new.
The larger the settlements, the more features and greater complexity they have.
Some are linked to the primary sector: coalfields of Asturias and Leon, Andalusian ruraltowns (oil), La Mancha and La Rioja (wineries), Levante and Murcia (horticulture).
There are cities with clearly industrial functions (Basque Country, Catalonia, Asturias, Navarra, Madrid metropolitan area).
Finally, major national cities (Madrid, Barcelona) specialize in business services, administrative or cultural. In the provincial capitals with little industry, services also tend to predominate, and there are some cities that specialize in certain types of tertiary activities: ports (Vigo, Algeciras, Las Palmas), tourism (Benidorm, Marbella), universities (Salamanca), etc.
Cities supply of goods and services to an area more or less extensive, depending on their size and what are their specialized functions.
The German geographer Christaller (1933) tried to implement a theoretical model of what would be a balanced system of nuclei, but urban areas are never as homogeneous: relief, borders or roads prevent it.