A Site of Community Interest (SCI), Lake Mezzano is a lake of volcanic origin, with rich aquatic vegetation and a large birdlife. An archaeological site of considerable importance, during the Bronze Age a vast pile-dwelling village stood on its shores, the remains of which are now submerged. The materials recovered in some underwater archaeological research, including numerous ceramic vessels and extraordinary bronze objects (axes, pins, a fibula and two bronze swords), are now on display in the Museum of Prehistory of Tuscia and Rocca Farnese.
On the western side, the remains of the Mezzano castle, destroyed in 1300 and dating back to the Longobard era, remain hidden. The lake is located along the third stage of the ‘Sentiero dei Briganti’ (which runs for about 100 km through two nature reserves, two lakes, a WWF oasis, two river systems and dozens of archaeological sites). The 3rd stage leads from the lake to Valentano.