The Milanese rail yards represent today seven major challenges for the future of the city. Distributed along a continuous ring which encircles downtown, it is highly probable that they will be the next areas of intensive development, giving another strong acceleration to the process that, in last twenty years, radically changed large sections of the city, transforming semi-central sites in new mixed use poles. These new settlements introduce, within the continuous of the historical and modern fabric, unusual morphological sets of various descent.