In Aachen, the historical axis of Jülicher Straße, an outstanding but quiet country road, long represented the main connection to the nearby city of Cologne. Only with Aachen’s industrial development during the 19th century did the city start growing beyond its historic city walls, and Jülicher Straße was transformed into an urban axis. From then on, different urban models were implemented along the street, in line with the planning visions of different decades. The further one moves from the city center, the more the historical compact city is replaced by an increasingly open city, a legacy of modernity. Thus, a single road allows one to retrace different phases in the modern development of Aachen’s urban forms and spaces. Given these qualities, the area around Jülicher Straße was analyzed in a seminar held by the Department of Spatial Design at the RWTH Aachen as part of the initiatives linked to the project ArchéA. This chapter presents the rationale and outcomes of the research, with a focus on the use of the red-blue plan to map urban spaces. Using the drawings produced for the seminar, this chapter illustrates how the study of Jülicher Straße permits retracing a century of Aachen’s urban and architectural history and thus highlights both the weaknesses and potentials of similar peripheral situations – strategic places for contemporary design.