Today, there are one billion people living in squatter communities worldwide, a number expected to double by 2030. 50% of our total urban growth will be informal, but only an estimated 5% of the design profession is occupied with the phenomenon of informal urbanism. Obviously an imbalance does not only exist in the global distribution of material wealth, but also in the provision of design capital. As a design profession we will have failed, if we do not develop effective modes of engagement with the informal that do not only transcend the dominance of pragmatism (the aid trap) but also bypass the increasing trend towards admiration (the glorification trap). GSD 6445 explores opportunistic design strategies for informal settlements that use the necessary provision of infrastructure as a pretext to engage in a deeper dialogue with the social, economic and ecological structure of the city as a whole. In customary solution schemes, it is often overlooked that informal cities are inseparably intertwined with the processes and transactions of the formal city. GSD 6445 will study tactical infrastructure interventions not only in informal districts, but in its efficacy in the larger context of the city in its region. Thereby we will use the metropolis of S++o Paulo with its 4 million slum dwellers as a case study. Landscape will be the basic platform of our investigation with a special focus on water infrastructures.