I will present a model for understanding a global network of local federations (Slum Dwellers International, SDI), by drawing on Edward Soja’s reading of Henry Lefebvre in the concept Thirdspace. The SDI network takes space as it’s bounding force in the struggle to transform the living conditions of slum dwellers in developing countries. My goal is to bring together the problem of slums with socio-political art movements of the 60’s and recent urban studies. The urgent problem of slums, that follow on the rapid urbanisation process worldwide is taken as a point of departure, using Thirdspace to see how the SDI network resolves the two conflicting scales to view the city – as pointed out by Lefebvre and Soja – the macro and the micro, by making the individual slum dweller an actor in a peer to peer exchange, while at the same time creating a social space for political struggle (in the city and globally). Through this process power is shifted from governments, international organisations and professionals to the lived space of the inhabitants. The paper is built on a case study from a slum upgrading effort in an informal settlement in Nairobi, Kenya that I undertook in 2003.