During the colonial period the Spanish American city was controlled by the Laws of the Indies, which dictated a gridiron street pattern developed around a central plaza, around which all major government offices, the majority of commercial activities and most social amenities were clustered. Consequently, employment opportunities were also concentrated in the city centre. Residential proximity to the centre was a symbol of social status. This pattern, which reflects the layout of Sjobergs pre-industrial city (see Chapter 3). remains a characteristic of many smaller Latin American cities. In larger cities. urbanisation and urban growth, especially since the Second World War, have been accompanied by several factors that have 'modernised' Latin American cities and transformed traditional urban forms. Griffin and Ford (1980) proposed a model of the Latin American city, subsequently updated by Ford (1996). that seeks to combine traditional elements of urban structure with the effects of moderninsing processes. As Figure 22.1 shows. the model is characterised by a downtown area, a commercial spine and associated elite residential sector, and a series of conccntric zones in which residential quality decreases with distance from the city centre.