The new research group on the four-dimensional research and communication of urban history (Urban History 4D) aims to investigate and develop methods and technologies to access extensive repositories of historical media and their contextual information in a spatial model, with an additional temporal component. This will make content accessible to different target groups, researchers and the public, via a 4D browser. A location-dependent augmented-reality representation can be used as an information base, research tool, and means of communicating historical knowledge. The data resources for this research include extensive holdings of historical photographs of Dresden, which have documented the city over the decades, and digitized map collections from the Deutsche Fotothek (German photographic collection) platform. These will lay the foundation for a prototype model which will give users a virtual experience of historic parts of Dresden.