Lake Balaton is a freshwater lake in the Transdanubian region of Hungary. It is the largest lake in Central Europe, and one of its foremost tourist destinations. As Hungary is landlocked (its coastline was severed after World War I), Lake Balaton is often affectionately called the "Hungarian Sea". The Zala River provides the largest inflow of water to the lake, and the canalised Sió is the only outflow.