Lago del Frassino is a small natural lake about two kilometres west of Peschiera, sitting in the moraine hills left by the last glaciers. It is a protected wetland, designated a Site of Community Importance under the European Natura 2000 network, and one of the few breeding sites in this part of Italy for the great crested grebe and the little bittern.
A footpath around the lake takes about an hour and is mostly shaded. The mix of reed beds and open water makes it good for birdwatching, particularly in spring and autumn migrations. Combine the lake with a visit to the Madonna del Frassino sanctuary nearby for an easy half-day outside the busier centre of Peschiera.