This chapter proposes a reflection on different European experiments of urban regeneration through “reuse” and transformation of urban areas. The phenomena related to global development and the current urban condition of our cities, induce to think about a different possible way of intervening on degraded areas. The reflection on vulnerable areas of the contemporary city based on the concept of Generic City introduced by Rem Koolhaas, relating to a specific way of thinking about the city that has lost its identity, to the theme of modification and the different meanings that this term has had in course of history. Another topic to be considered is a reflection on the role of architecture in the 'ongoing process of change in the city. Observing the city, identifying the cores, starting from the identity, is one of the possible ways to make sure that the planning tools are more closely linked to the needs and character of the place rather than instruments of the transformation imposed from above. As part of its improved management of resources and focusing on "architecture" as a tool useful for the city and its citizens.