At the Archaic and Roman site of San Basilio di Ariano nel Polesine, the conditions for geophysical prospection are extraordinary, as we discovered during a series of magnetometer surveys between 2020 and 2024. In this contribution, we explain the approach and method applied at San Basilio and review why it worked so well at our site. Moreover, we discuss how geophysical data enhance our understanding of the site in conjunction with the ongoing excavations and geoarchaeological work in the Po delta.