The article describes the stability conditions of the rock mass of the summit part of the Grave in Grotte di Castellana (Puglia, southern Italy). The geometric reconstruction, the geological, stratigraphic and mechanical characterization adopted for the safety status checks according to the NTC are illustrated, through 3D FEM modeling. Direct (continuous core drilling) and indirect (seismic profiles and MASW) geognostic investigations were carried out. The surveys highlighted the presence of layers of variously fractured limestone rock with average RQD values ​​equal to 55%. Rock samples were taken and subjected to laboratory tests for the recognition of physical and mechanical parameters (compression and traction). The quality of the rock mass was also assessed with Bieniawski (RMR), Burton (Q) and Hoeck & Marinos (GSI). The reconstruction of all the geometric elements of the 3D CAD modeling was created starting from the point clouds, obtained from photographic survey and laser scanner, and used for the subsequent 3D FEM finite element modeling with the Midas FEA software.