This chapter addresses situational crime prevention in the city of Porto Alegre, empirically investigating three subcultures and social spaces: groups of guard dog breeders, a shooting club and a weightlifting and self-defence gym. The thematic focus integrates the subjects of violence prevention, administrative criminology, self-protection, and cultural criminology. It examines the informal control of violence within groups where aggression acts as a reactive, motivating, or consistent element in the group’s practices. The methodology adopted is that of cultural criminology, urban sociology, and urban anthropology, with questioning of empirical data obtained through ethnographic insertion into these subcultures. The appreciative posture adopted during the ethnographic study and the conceptual treatment of empirical material led to a comprehension deeply rooted in a detailed description of the reality experienced during the ethnography. These spaces served as arenas where personal empowerment and collective identity were expressed, illustrating subcultures focused on preparedness and self-reliance. Through activities like the development of workout plans or the selection of defensive tools, participants exhibited a sense of vigilance, influenced by underlying insecurities that shaped their physical routines and interpersonal interactions.