What constitutes modern Mexico? Is there a clear distinction between the historic and modern Mexico City? And if there are, does this distinctions hold up throughout the twentieth century, when what is apparent is a mix of legacies coexisting overtime? This chapter discusses the semiotics of history and modernity. It discusses the struggle of the Mexico City to find its own image including its struggle to preserve historic buildings amidst the differing political alliances that either promote change or preserve the past. However, past is not a single entity, hence if the preservation of the rich history of Mexico is pursued, the question arises as to what periods of history represented in the city are to be favoured in its future development. In this chapter, the focus is on the paradoxes of the Torre Bicentenario and on the pressures to preserve Mexico’s past, the ways they have been juxtaposed against the plans for its future and how the balance of these views has shifted over time. It determines the key actors and the institutions who have embraced history as opposed to progress, identifies the set of forces that dominated in the city’s twentieth-century history, and assesses the long-term implications of the shifting balance for the social, spatial and built environmental character of the city. The chapter ends with a discussion on the current role played by the cultural and historical authorities in determining the fate of the city.