The collection consists of historical records and a corpus of 269 black and white photographs taken during the Milan subway building. Collected by Luigi Zaretti, engineer chief of the subway Line 1 between 1957 and 1963 for society M.M., the Fund consists of seven classifiers of photographs and in a box that contains material design and documentary concerning the activity of Zaretti: plans and sections of the stations, maps, financial and structural calculations, such as studies of developments of constructive procedures for tunnels underground, surface studies of underground prefabricated structures implemented by the excavations in the trenches, as well as the dossiers with the technical description of the underground structures the Alpina S.p.A. (Milan). Photographs were taken during the work and come from various agencies, including Publifoto, Cera Foto Servizi and Photo News Giancolombo directed by Gian Battista Colombo.