My dissertation analyzes the work of the artist group 3Nós3 (the name is a pun in Portuguese meaning "three knots/ we three"), who performed artistic actions in public space that they referred to as "urban interventions" on the streets of São Paulo from 1979 to 1982. These ranged from placing garbage bags over the heads of monumental sculptures to taping Xs across the doorways of art galleries along with signs reading "What is inside remains the same; what is outside expands." Within the context of the military regime that had ruled Brazil since 1964, the urban interventions targeted symbols of authority ranging from public sculpture to the art world establishment. My research focuses on one of the most noteworthy traits of the group's activities: their almost complete absence from the history of Brazilian art. In spite of the recent popularity on the international artistic circuit of contemporary Brazilian art with a performative edge (the artists Hélio Oiticica and Lygia Clark being the best examples of this type of work) the work of 3Nós3 has remained obscure, even within Brazil. The explanations for this lack of attention to 3Nós3 include the transitional political nature of the abertura period during which the interventions took place, the artists' own denial of traditional artistic circuits and involvement in youth subcultures, the ephemeral nature of the interventions themselves, and a lack of understanding of the reasons why the artists chose to work in public space, particularly in regard to the interventions' relationship with their audience. The goal of my dissertation is to argue for the inclusion of the interventions into the history of art without relying on arguments related to their quality, i.e. whether or not they constitute "good art." Rather, it is only through a detailed consideration of the specific cultural and political contexts in which the works occurred that they start to make sense. I conclude by examining the present-day conditions that could make the inclusion of 3Nós3 into larger international artistic movements such as street art and "the interventionists" (including Eduardo Srur and the Grupo Contra Filé, among others) possible. / text