Educational practices that developed under the conditions of the military siege of Sarajevo during the Bosnian War (1992-1995) are examined. Analyses of interviews with teachers and students are juxtaposed with archival documentation to reveal the mode of educational activities and the structure of the curriculum implemented. By exploring how different conceptualisations of space and time rendered by the condition of the siege prefigure different human activities, the development of educational infrastructures across the besieged city are traced chronologically. The analyses highlight two educational forms: "War Schools" a network of makeshift mixed-age underground classrooms and "Radio School" daily educational broadcasts--together with the curricular innovations they engendered. Departing from a focus on individual outcomes such as deficits, trauma, and aggressive behaviours, this work instead argues that collective educational activities have the ability to constructively mediate threatening external circumstances and support young people's psychological capacities even during the times of crisis.