This article reports on a multi-resolution and multi-sensor approach developed for the accurate and detailed 3D modelling of the entire Roman Forum in Pompei, Italy. The archaeological area, approximately 150 — 80 m, contains more than 350 finds spread all over the forum as well as larger mural structures of previous buildings and temples. The interdisciplinary 3D modelling work consists of a multi-scale image- and range-based digital documentation method developed to fulfill all the surveying and archaeological needs and exploit all the intrinsic potentialities of the actual 3D modelling techniques. The data resolution spans from a few decimeters down to few millimeters. The employed surveying methodologies have pros and cons which will be addressed and discussed. The results of the integration of the different 3D data in seamlessly textured 3D model are finally presented and discussed.