The Expression of Illegal Urbanism in the Urban Morphology and Landscape: The Case of the Metropolitan Area of Seville (Spain)

Illegal urbanism has been, and still is, an inherent aspect of the metropolitan fabric of many Spanish cities shaped throughout the twentieth century. The morphology of these complex spaces, with origins in organic growth processes, reflects illegal housing developments through discordant, poorly connected networks, often with significant landscape and environmental impacts. The metropolitan area of Seville, comprising almost 5000 km2 and more than 1,500,000 inhabitants, is a paradigmatic space where these facts can be traced, especially in its western sector, where the strong urbanisation dynamics of the last decades have reached and engulfed many of these housing developments. This work establishes an analysis and proposes typologies of the different repercussions of the process in this territory. It does so by drawing on, among other sources, two regional inventories on illegal urbanism, which allow the application of a diachronic perspective and fieldwork with information synchronised to the present time. The main conclusion is that, in addition to explaining the complex metropolitan networks in which they appear (justifying singular forms, asymmetries, and morphologies), the illegal housing developments analysed are an important element for weighing the sociopolitical characteristics of the municipalities in which they are inserted.