The pattern of the grid city now seems dated and far from the metropolisation phenomena that characterize contemporary cities. In fact, as already happened in the past, the grid cities manage to evolve favoring the needs of its contemporary inhabitants. In this chapter, the authors try to understand some phenomena that characterize the transformation of the urban form of the grid city, highlighting its own ability to evolve between tradition and innovation. During these 200 years, the grid city, its buildings, and its public spaces were created, lived, and processed in multiple ways: built, replaced, drawn, renovated, restored. Here, the authors do not want to describe these planning and building tools, but they want to discuss the possible implications of the different transformation modes used in the grid city can have on urban and architectural perception of the physical space, the quality of life, and viability of these central places for the city's identity. The city of Bari, on the Adriatic Coast, in the South of Italy, is used as a case of study to represent concepts developed in the chapter.