The historic centres of many cities have interior underground cavities or empty spaces dating from different periods. This paper establishes guidelines for systematising and simplifying the collection of data from underground heritage spaces, with the ultimate aim of facilitating the management of the information obtained and encouraging the conservation and public appreciation of this type of heritage hidden beneath the surface of our cities. The case study selected is a Roman cistern belonging to the network of underground heritage structures in Carmona. The photogrammetric survey conducted presented an additional complexity due to the small size of the space and its underground location. As the next step in the research, a 3D model is created. Lastly, a set of optimised strategies specific is proposed to the unique nature of this type of heritage
