This dissertation brings sharp social theory, deep history and precise ethnography to illumine the nexus of social and urban structure, human emotions, and power. I draw on Norbert Elias, Emile Durkheim, Marcel Mauss, among other social theorists and historians, to counter dominant views of fear in the social sciences as a sole destroyer of the social fabric with evidence of how and why fear both tears and tightens the social fabric, both destroys and fosters solidarity. Yet with the exception of a few spaces of hope where families of victims of forced disappearances organized to demand justice from the state, this “tightening” of the social fabric did not transcend but rather exacerbated socio-spatial divides. I draw on comparative urban sociology by Teresa Caldeira, Gerald Suttles and Loïc Wacquant to trace the revamping of San Pedro, a suburb of the Monterrey Metropolitan Area and one of the wealthiest municipalities in Mexico, as an emerging state within a state for the upper class—an example of a new pattern of urban seclusion taking form in Latin America. This dissertation contributes to the sociology of everyday life in the city and the political sociology of fear and violence by providing a rare case study of cross-class responses to gruesome violence.