At the 30th km of the national road Ioannina-Arta, near the village Vouliasta, the natural lake Viros is located, which is formed by the sources of the river Louros.
It is located at an altitude of 296 m, has a circular shape, with maximum diameter of about 93 m, perimeter around 300m and maximum depth 10,2 m. The lake Viros is fed by underground karst watercourses and lets a surface opening only to the east, through which its waters feed the river Louros. Viros is called the sharp fall of a river, the whirlpool or the deep waters. A rich aquatic flora but also fish, frogs, crustaceans, insects and aquatic animals are encountered at the lake area.
