This paper aims to contribute to a discussion about the transformations of the values of urban form as a movement of the collective imaginary. That becomes recognisable in the city form and creates the image of a city as something that is not substantial, palpable or that may be deciphered. It has a case study: Rio Branco Avenue, in the centre of Rio de Janeiro. This is the principal axis of the urban structure of the city centre. I intend to analyse two urban interventions on this area in two moments: at the beginning, and in the last decade of the twentieth century, in the sense of recovering the importance of the avenue as a monument, as an urban structure, and as a space for the citizens act in public life.