Lake Biwa is Japan's largest freshwater lake. It occupies almost one-sixth of Shiga Prefecture, where it's located. It has a circumference of 277 kilometers (172 miles) and its water surface spans an area of 672 square kilometers (259 square miles). At its deepest point, it measures 104 meters (341 feet), although on average it's about 40 meters (131 feet) deep. The lake is fed by 125 rivers.

Designated a quasi-national park by the Japanese government, it's thought to be one of the oldest lakes in the world--about 5 million years old! The water from the lake is used not only for drinking but also by farmers and factories.

It's home to many freshwater fish, including the trout and carp. Freshwater pearl culture is also a prominent industry in the area.

Photo by Otsu Kids' Eco Club.