This paper offers a commentary on Maurice Halwachs’ writings on “collective memory” in the years between 1925-1945. Architectural and urban spaces figure prominently in work of the French sociologist since he maintains that memories survive in the longue durée only to the extent they are indexed into architectural places, and mapped into an urban and historical topography. This comes with a caveat: in his pioneering study of “collective memory,” La topographie légendaire des Évangiles en Terre Sainte: etude de mémoire collective, Halbwachs highlights the discrepancy between the archaeological record preserved in material culture—for example ancient ruins and monuments—and the living memory of a religious community. Likewise, in his study of working classes, Halbwachs’ neologism, “collective memory” is defined as a deliberately unstable, and socially constructed category. The provisional and fluid definition that Halbwachs assigned to “collective memory” offers an insight into our present predicament. In the last decades, the ability of architecture, urban design, and architectural conservation in framing and preserving a stable and unified cultural heritage has been profoundly challenged. This paper makes the case for moving away from merely technical inquiries that understand architecture and places as “sites of memory” to a new direction that builds upon Halbwachs’ social frameworks of memory. It is thanks to Halbwach’s pioneering, if incomplete, work on “collective memory” that we may understand how the emerging and open-ended social formations transform architecture and urban spaces.