The thesis has as its theme a broad reflection on the fire that occurred in 1978, at the Museum of Modern Art of Rio de Janeiro. It is based on the assumption that the fire, which destroyed almost its entire collection, could be a symbolic milestone of the rupture of the modern project that would have MAM as one of its bases. The modernity model sought by MAM is discussed throughout the text, in order to formulate and analyze the possibilities of fracture regarding this model. In its structure, the thesis builds a network of articulations around the condition of ruin that the fire materializes, addressing cultural and social issues that were dear to Brazil and the world in the second half of the 1970s. For this purpose, the thesis was divided into three blocks: What burns, the work of fire and the ashes. The first block lists the issues related to the modern project, the idea of a modern museum as a construction of memory of the future, and the conditions of this project s rupture, based on authors such as Octavio Paz, Artur Danto and Jean-François Lyotard. The second block discusses projects that reflect the change in perspective that was underway. Among them, the proposals brought by Mario Pedrosa for MAM s reconstruction, the postmodern museum of Frederico Morais, and the printed museum of the Malasartes and A Parte do Fogo magazines. Lastly, the third block raises the issues of an archive that, as it was ruined, would need to be reinvented. In this part, fiction emerges as a conceptual strategy to guide the narrative and fill in certain gaps. Real documents are brought to the fore by characters such as a blind curator, a distracted archivist and an archivist artist, discussing the change in the visuality regime that would shape the transition from modern to contemporary. Following this drift between fiction and reality, artists Cildo Meireles, Tunga and Artur Barrio have their works analyzed based on aspects that are detached from a retinal appeal. The text, while discussing new image production regimes, establishes a parallel between these artists and the history of the Museum of Modern Art of Rio. In the end, it is established that the change in perspective from modern to contemporary could not be isolated by a single event, however, by reinforcing an ongoing rupture, the MAM fire could be considered a symbolic milestone of this event.