The Regional Natural Park of Bracciano-Martignano lake complex is a protected area of ​​great naturalistic value between the lakes of Bracciano and Martignano. Both lakes are of volcanic origin, set between the Sabatini mountains and are known for their crystal clear waters. Perhaps this is why the area has been frequented by humans since the Lower Paleolithic and necropolises of various ages have been found.

This area has many naturalistic features protected by the Park of the two lakes of Bracciano and Martignano. Inside the park there are also the Caldara of Manziana, the Faggeta of Oriolo Romano, the Pantanelle and Lagusiello. The lakes occupy the bottom of a basin linked to the activity of an ancient active volcano some 400,000 years ago. 159 species of birds have been sighted, of which 72 nesting in the Park.

Bassano Romano is included in the Natural Reserve of Bracciano-Martignano lakes and its territory is characterized by a particular beech forest. An immense wood of fairy-tale appearance, unusual at an altitude of only 500 meters above sea level. The forest is owned by the Agricultural University of Bassano Romano, which has created an area equipped for picnics.

Anguillara Sabazia is also located within the regional natural park which includes the area between Lake Bracciano and the small lake of Martignano.