TOPORAZ focusses on the topography of a quarter of historical Nuremberg, which is displayed at three to four time levels: the early modern period; (1870), 1939; and the present. The representation consists of geo-referenced 2D maps and 3D models and a factual database covering buildings, furnishing, iconography, persons, and social networks. Maps and 3D models serve as a structure for navigation and help visualizing results from database queries. The information is maintained in a relational database which implements a semantic data model heavily influenced by CIDOC CRM. This approach enables researcher to query for facts like ‘Who inhabited a building at a given time?’, ‘How did a building evolve through history?’ or ‘Who donated this statue and where is it located today?’