Design has commonly developed a minor role in the diverse and complex processes that constitute a city. The intangible dimension of the city has been led by social sciences and economy. Its built dimension has been entrusted to urban planning and architecture in the definition of the fundamental threads. The development of urban planning since 15th century highlighted the key role of the urban plot in shaping the city. This plot was defined by a precise balance between the built mass -expressed by buildings- and the controlled void -that of streets, squares and parks. In this context of primacy of architecture, design played a minor role, completely subordinate to the main threads previously defined by urban planners and architects. Urban design used to appear when the key features of the city were defined and even built. Therefore, design was completely conditioned by pre-existent elements that couldn’t be questioned or transformed.