Jaques Ranciére (2009b) argues that if there is a political question in contemporary art, '...it will be grasped through the analysis of the metamorphoses of the political 'third', the politics founded on the play of exchanges and displacements between the art world and that of non art' (2009b:51). Looking at graffiti and street art in Barcelona as 'textures', which stimulate the mind, body and senses. I have investigated what public space means for its inhabitants through the material nature of the surfaces by which it is contained and by applying media devices. This has led me to develop an ethnography of encounters, perceptions and sensibilities linked to political practices and different modes of participation in the everyday life of the city. Following Jacques Ranciére's (2004) conception of 'political aesthetics', I argue that the aesthetic of graffiti and street art can be embodied according to different sensible orders in the city. The public space is key in this process and I see it as an interface between graffiti artists, the general public and the institutions of the city. Graffiti activate the urban landscape through visual and tactile transformations of space through surfaces. These interactions, as De Certeau (1985) claims about everyday practices, may articulate narratives, which became the main source of information for this thesis. Thinking about the graffiti works in Barcelona in terms of Bakhtin's (1981) idea of 'the chronotope', I have recounted the stories, which make the transformation of public space indicative of the everyday life of the city applying practices of collaboration, dialogue and intervention. These practices connected me to different surfaces of the city so as to explore how their material qualities are permeated with social relations and artistically inscribed with historical and political meanings. Here, graffiti and the city formed a compound of images in which I have studied the 'visuality' of graffiti in Barcelona. This, as Hal Foster (1988) argues, encloses at the same time social facts and physical operations (body and psyche) and moves, as I will show throughout this thesis, between dominant and resistance cultures. In short, I have materialized these ideas and images in the graffiti texture of Barcelona, seeing it as a mutable surface, which mediates between different ways of seeing and living in this city.