The aim of the present work is the virtual reconstruction of the synagogues in Gänserndorf and Bohumin. The synagogue of Gänserndorf was designed by architect Jakob Modern and buildt in 1890. In 1938, under the National Socialist regime, the building was expropriated and since then adapted to various changing functions. During these conversions, the external facade was removed. The rebuilding measures were so profound that today, with the exeption of a memorial plaque, nothing reminds of the original function as a synagogue. The temple of Jakob Gartner in Bohumín, Czech Republic was built between 1901-1904, and completely burnt down between 1939 and 1940. The basis for reconstructing a 3D-model was a postcard, as well as a city map with the ground plan of the ground oor of the synagogue, which was not the original oor plan. The work is divided into the background and context of the synagogue in Gänserndorf. An overview of the works by Jakob Moderns lend an insight into the repertoire and the work of the architect. The results of research and analysis are also presented here. The second section deals with the reconstruction of synagogues. The transfer of the collated material and the insertion of these into the respective programs are explained. The individual steps in the 3-D-modelling and the subsequent photorealistic representation provide precise descriptions and make the work process comprehensible.