A cuniculus was revealed during work on the land development scheme known as San Celso 2. This ancient tunnel, cut into the bank of Tufi stratificati varicolori de La Storta, has the typical ogival profile of those examples built as part of the water supply system in the territories of Caere and Veii between the 6th to 4th century B.C. and in the mid-late Republican period. The structure is orientated on a WSW-ENE axis in the direction of Lake Bracciano and is completely blocked by a sedimentary deposit. It is 1.71m high, 0.49/54m wide at the base and 0.57m wide at the vault impost. The base of a black glaze situla, Morel 6521c1, a type attested in Etruscan areas between 340 and 300B.C., confirms the structure's chronology and possible continuity of use during the Roman conquest of the Sabine territory around the lake, which began after the capture of Veii in 396B.C. and ended around 273 B.C. In the past, a spring is said to have been found a short distance uphill from the cuniculus, and it is possible that the water supply system may have been built to exploit this resource. This hypothesis is reinforced when the known occupation of the south western side of the lake during the Republican period is also taken into consideration. (Roberto Manigrasso)