The interactive digital diorama of s.Carlo square, the most important and beautiful of the city of Turin, has been made by the Ultramundum Foundation upon request from the city Council, mobility division. We want to thank these people for giving us the opportunity to create the model of such an imporant area of a big city like Turin. This model covers the square, via Roma (Turin large main street) from Castello square to the Porta Nuova rail station. From Castello square the important Po street has been modeled up to Vittorio square and the Po river. It is a very large area, covering all the Turin historical center. Under s.Carlo square has been inserted the 3D model of the underground parking and, under it, that of the bombing shelter from the second world war, at 30 meters below surface. For many citizens this has been the only chance of ever visiting the bombing shelter, today closed for security reasons. The interactive model has been installed in Atrium, the city exposition pavillon so that the public has been able to explore that underground area. Without UltraPeg technology this product could never be made in the time and with the costs allowed by this new production method. Standard systems, then, would not allow for Internet download and would require a CD-Rom. All the model is explorable in real-time on a standard PC with a 128Mb video card. The Foundation can arrange interactive demonstrations on request, because this product can not be freely distributed yet.