This chapter explores the link between space, affect, and political participation based on an analysis of the occupation of urban squares as spaces of political contestation and transformation. Drawing on fieldwork on the uprising in Egypt in 2011, first is a thick reading of Tahrir square as an affective and material space. Then Midan Moments is introduced to conceptualize the affective dynamics during the 18 days of occupation in January 2011, which refer to periods of rupture on a delineated space that are characterized by intense affective relationality through the bodily co-presence of protesters and their practices on this space. The concept of the Midan Moment allows for an analysis of space, affect, and political participation that can account for the non-linear, and at times contradictory, developments during and after mass mobilizations on public squares. Sustained practices of protest on the occupied square are embedded in a complex web of affective arrangements that are marked by capacity and potentiality which enable – at least momentarily – an overriding of deeply ingrained gendered, political, economic, religious, or ethnic cleavages. Yet, while Midan Moments do hold the possibility for political transformation, they are also marked by ambiguity and limitations.