The full beauty of lake Sartai and the landscape relief of Sartai regional park formed by glaciers thousands of years ago opens from the observation tower, located in Baršėnai village Rokiškis district, in territory of Sartai regional park. Tower was built with private funds in 2006. The height of the tower is 33 meter.
Sartai is the fourth largest lake in Lithuania. The largest lake width is 950 meters, the average is 500 meters. The coastline runs around 80 kilometers. There are 7 islands on the lake. The largest island is 6.5 hectares.