摘要:The study addresses the problems of acquisition and enhancement in the field of underground sites with particular regard to the Catacomb of St. John in Syracuse. In addition to the proposed survey methodology, the research highlightes that only through a reliable and objective documentation you can understand and study in depth these places. 3D documentation of these places hidden from the eyes of the city and, therefore, very complex to interpret has provided a powerful tool for investigation as it has allowed to show the relationships between the plano-altimetric environments and to study from a geometrical point of view the spatiality of these places providing new and valuable information to scholars of the monument.