On the border of the regional units of Xanthi and Rodopi, lake Vistonida (or Bistonis) is one of the most well-known lakes in Greece with a very interesting history. It was named after the city of Vistonia (or Bistonia), which was founded by the mythical Biston, and was the home of the Bistones. The lake is mentioned by many writers, geographers, and travelers. Access to the lake is from the nearby villages of Selino, Nea Kessani, Koptero, Salpi, Nea Kallisti and Glykoneri.

It is the fourth largest lake in Greece covering an area of ​​45 square kilometers, with an average depth of about 4 meters. It is part of a complex of wetlands and part of the National Park of the Nestos Delta; Vistonida and Porto Lagos are considered as top ecotourism destinations in Greece.

It is a brackish lake that is fed by the rivers Kosynthos, Kompsatos, and Aspropotamos. It ends in small lagoons, some of which are used for fish farming. To the south, it is separated from the Thracian Sea and the Vistonic Gulf by a narrow strip of land, where the wetlands of Porto Lagos extend; to the north, the lake reaches almost to the foot of the Rhodope Mountains. The wetland complex is protected by the Ramsar Convention.

In Vistonida you will find an ideal place for observing various bird species all year round. Out of 260 species, 9 are rare or endangered, such as the white-headed duck and the lesser white-fronted goose.