Urban archaeological prospections: The GPR investigations close to the Caracalla Baths in Rome (Italy)

The presence of the modern “Nando Martellini” athletic stadium, which is near the Carcalla Baths, in the center of Rome, is just one of the several cases in which GPR investigations can assist with the urban archaeology of the so-called Eternal City. The Domus septem Parthorum (the House of the seven Parthians) is a monumental ancient complex that has not been wholly excavated and whose functional purpose has changed over the centuries from public to private and finally to religious. The main aim of this new research is to understand the archaeological evidence beneath the soil that was partly discovered by the 1986–1999 excavations. In particular, this GPR (Ground Penetrating Radar) research is focused on better defining the buried ancient structure by using a high vertical and horizontal resolution to highlight the shallow top of the buried standing walls. An ERT (Electric Resistivity Tomography) approach should confirm the GPR results. It is confirmed that the anomalies result from a Late Antiquity domus (Roman house) that was likely reused later as religious building (i.e., a Paleochristian basilica) with a rectangular geometry, according to the visible apse. Considering the several reuses of the area over time, including the recent construction of the modern athletic stadium, the non-destructive acquisition of important geophysical information is essential in urban archaeology not only to obtain a coherent answer to a historical interpretative problem but also to form a coherent understanding of urban evolution.