This paper illustrates the methodology, technological solutions and interaction metaphors chosen for the development of a 3D immersive Virtual exhibition that aims at enriching the visit of an important part of the historical cultural heritage of the city of Trento, in Italy. The goal of this work, supported by the local authority for Cultural Heritage, was to implement a user friendly virtual environment, which could show to the visitors the significance of the archeological findings of the ancient Roman town of Tridentum, despite the peculiarity of the siteis premises, located below a square among a theatre foundations. Outcomes of the research work are a high-quality and scientifically correct reconstruction of the Roman town in various historical eras, thanks to fruitful interaction with archeologists, and the development of an ad-hoc user-friendly immersive virtual environment implementing a customized interaction metaphor for the fruition of the virtual reconstruction. The developed interface allows users speaking different languages to share simultaneously the experience of virtual tours across time using a joystick. The whole environment has been developed to become a permanent virtual exhibition in the premises of the archeological site.