Borders have always accompanied ours cities, understanding their role before the urbanization process and within the urban fabric is an important aspect in order to figure out how to improve the critical point of the encounter of the city and borders. To begin with, is important to define exactly what a border is and its different embodiments have been illustrated within the city of Rome. Furthermore, is interesting to analyze the active influence a border has, capable of conditioning entire urban processes, leaning in the case of Testaccio this statement has been studied. From an architectural point of view is essential to accept the dual value of borders, “border conditions” often decline into a ‘’no-man’s land” but at the same time they are places of potential building recurrently ignored. As a result, the project deals with a problematic zone due to the presence of various borders.