I set out to consider the modernist ideological position that to build in a city one must first demolish what exists: one must make room for utopia.¹ Urban erasure is ideological, and that ideology is material. Processes of urban erasure, of urban demolition, of slum clearance and of land terraforming require structures of legitimacy to be enacted, and those structures of legitimacy are produced through materials. Materials that produce the legitimacy for urban erasure in the following case of a site in Mexico City in the 1960s, materials like paper, ink, graphite, typewriters, bound journals and texts, printing presses and...