Museu Nacional: memory and post-trauma cultural heritage is a research that seeks to deepen the layers that make up the Museu Nacional before and after the fire in 2018. The questions raised come from the trauma that occurred and the reports of this event, but also from the history of the Museum from the perspective of heritage, understanding the evolution of its concept and the different currents of conservation at national and international level. The research prioritizes Alois Riegl s general theory of values, which defends the need to reconcile elements of the past and present in the contemporary city, as well as analyzing the current scenario of cultural heritage in a globalized society. It seeks to unravel the elements of the patrimonial discussion capable of valuing a building, and why its need for preservation makes it unique and irreplaceable, just like its cultural significance. In addition, it seeks to deepen the theme of collective memory – initially described by Maurice Halbwachs – social and individual, relating them phenomenologically to the formation of identity and place. Trauma enters the research under a temporal perspective, a new variable in the relationship and identification between people and the Museum, before and after the fire, seeking directions and references for reconstruction. Finally, the research promotes an analysis of the current situation and the conceptual project disclosed for the reconstruction of the Museu Nacional and the objectives behind the proposal.