In the last few years, the open-source desktop planetarium program Stellarium has become ever more popular for research and dissemination of results in Cultural Astronomy. In this time we (LBI ArchPro and TU Wien) have added significant capabilities for applications in Cultural Astronomy to the program, in particular a way to allow virtual 3D exploration of architecture from any period. The major part of this chapter describes our recent accomplishments for allowing its use in a multi-screen installation running both completely automated and manually controlled setups in an exhibition about Stonehenge. During the development time, also the accuracy of astronomical simulation has been greatly improved. The final part of this chapter (authored by B. Frischer) presents the latest application examples, in particular of these 3D capabilities, for Cultural Astronomy research in the Roman world.