The rapid urban growth of Brazilian cities in the second half of the twentieth century produced an extremely unequal urban fabric with spatial discontinuities and left-over spaces. Spatial fragmentation in Brazilian metropolises is not only related to spatial discontinuities, but also to socioeconomic inequalities. Walls in Brazil are physical and social. This fragmentation undermines the resilience of the urban system, which depends on the cooperation capacity between actors in the face of unexpected changes. Since the physical connection of disconnected spaces does not necessarily create social connections between segregated groups, it is difficult to develop cooperation and thus resilience in fragmented cities. In this context, this thesis presents self-organised initiatives as potential actors to dismantle these invisible walls. Self-organised initiatives promote the creation of social connection between highly diverse groups in public spaces of cities with extreme socioeconomic inequalities, which has a positive impact on the resilience of the urban system. Aiming to establish a solid societal impact, the thesis puts forward recommendations on two fronts: education and practice. The author demonstrates, based on the experience of the massive open online course Rethink the City, the way how doctoral research can be used in open online education. Grounded on the findings in the cases of Brasília, Rio de Janeiro and São Paulo, the thesis lays out a set of recommendations on how urban planning can work with self-organised initiatives in a collaborative manner in order to foster social connection in cities with patent socioeconomic inequalities.