Rosa Fernandez and Jean D’Aragon’s article on slums and disaster risks, makes a strong argument that the form or morphology of these settlements has an important influence on their level of vulnerability. While the configuration of these settlements is indeed a key factor, the choice of location for housing of poor families or new migrants to the city is usually based on a complex set of economic and social choices (or possibly lack of choices). Slums are not always spontaneous and are often not the results of invasions or occupations. Many slum dwellers have purchased the land that they have built their houses on and have documents to prove it. However, rarely do these documents have the weight of legal title. Therefore slums are usually considered as illegal by government officials and town planners while the occupiers of housing in these areas may feel that they have acquired their home through legitimate market means. In most African cities the large majority of residents live in areas without legal tenure because they have no other choices. Urban planners have often not provided affordable options for the poor to acquire environmentally secure, minimally serviced and low-risk sites for housing construction.