This article examines the effectiveness of defining public space in subway stations in Mexico City as media, especially for the purpose of nation-building or Mexicanization. The stations are natural places for people to congregate and many are adorned with murals, objet, replicas of pre-Hispanic ruins and walls, and even expositions. These displays constitute an important example of historical representations of the nation and national culture. The paper examines the function of these public spaces as a vehicle for sending messages to commuters and passengers, and also the processes of self-representation of Mexican people.