The researchers have been using an established technique known as magnetometry, which involves systematically and rapidly scanning the landscape with small handheld instruments in order to identify localised magnetic anomalies relating to buried ancient structures. These are then mapped out with specialised computer software, providing images similar to aerial photographs, which can be interpreted by archaeologists. In antiquity, the landscape in this recent study was known as the Isola Sacra and was surrounded by a major canal to the north, the river Tiber to the east and south, and the Tyrrhenian sea to the west. At the southernmost side of...