Cities used to be surrounded by walls. Today, where walls were built, cities have incorporated them into the expanding urban fabric. The rise of urban populations and the increasing movement of temporary populations through cities have radically altered the social fabric of urban spaces. The contemporary metropolitan urban form is indeed quite different from that of a traditional settlement, which coincided with the resident population. Cities attract a variety of different populations; they are traversed by mobile and temporary populations that continually reshape the relation with the land. Quite prophetically, in 1993, the leading Italian sociologist Guido Martinotti wrote:\u00a0\u00a0<\/p>\n\n\n\n
Of the total population that gravitates to the city, the proportion of the population that uses it, but is not ‘responsible’ for it, tends to increase and perhaps will eventually outnumber even the total population that uses the city but also inhabits it, and is therefore responsible for it <\/em>(Martinotti, 1993, p. 166).<\/p>\n\n\n\n In his seminal book Metropoli, La nuova morfologia sociale della citta\u0300<\/em> (Metropolis, The New Social Morphology of the City<\/em>), Martinotti (1993) describes the different social formations connected in contemporary urban space, layers adding to and transforming the traditional town into a new entity: the modern urban metropolitan area, a functional system more than a spatially defined structure. The following quotes are from Martinotti\u2019s paper The new social morphology of cities synthesizing a lecture held in Vienna in 1994.<\/em> To explain \u00abthe great mutation\u00bb affecting contemporary cities, Martinotti (1994) proposed to \u00abrepresent schematically various types of urban morphologies by using a simple combination of four populations differentiating out in successive phases\u00bb. The inhabitants, or the population living in the city, which in the traditional city largely coincided with the population working in the city; the commuter population, whose growth took place in the USA from the Twenties and in Europe after War World II. The commuter population is concentrated in the city centre and remains Martinotti notes that \u00abthis is a swelling population that has increasing effects on the structure of cities and actually uses them in a rather uncontrolled way\u00bb. The proportion between inhabitants, commuters and city users varies among cities \u2013 Venice, already at the time of Martinotti\u2019s writing, being an extreme case of disproportion in favour of city users compared to other populations. Martinotti identified a fourth metropolitan population made up of metropolitan businessmen, a relatively small but growing group Aside from the description of the four populations and of the new types of urban morphology they give rise to, a second aspect of Martinotti\u2019s theory, in fact a cornerstone in Metropoli, is worth recalling because of its strong relevance to the current state of cities in Italy: the inability to assess urban transformations by changing populations due to the inadequacy of traditional statistical data based mainly on residency. The size of the population of city users is growing, Martinotti writes,\u00a0but it is
mostly separated from the rest of the city population, Martinotti argues, and has led to the formation of a new entity: the first-generation metropolis largely based on commuting basins and embodied in the concept of metropolitan area. Further differentiation of populations arose from innovation within the transportation system: \u00abthe increased mobility of people, combined with the availability of greater income and leisure, allowed the differentiation of a third population in our diagram, the city users\u00bb.<\/p>\n\n\n\n
according to him, a product of the service industry (similarly to city users) disposing of a \u00abconsiderable availability of both private and corporate money\u00bb, carrying out activities that require \u00abintense and repeated face-to-face interaction\u00bb. This transnational middle-class population living between cities signals the globalisation of metropolitan centres. One of the major effects of globalisation and of the growth of this fourth population, Martinotti argues, is the increasing homogenisation of cities that once
\u00abembodied the specificity of local culture and traditions\u00bb. The presence of these four populations, according to Martinotti, characterises the third-generation metropolis, which is still emerging.<\/p>\n\n\n\n
difficult to assess. Precisely because all our collective cognitive apparatus is geared to a traditional city that is undergoing a profound mutation, and statistics still deal mainly with inhabitants, to a smaller degree with commuters, but practically in no way with users (Martinotti, 1994, p. 166).<\/p>\n\n\n\n