琵琶湖
Lake Biwa is of tectonic origin and is one of the world's oldest lakes, dating to at least 4 million years ago. This long uninterrupted age has allowed for a notably diverse ecosystem to evolve in the lake. Naturalists have documented more than 1000 species and subspecies in the lake, including about 60 endemic. Lake Biwa is an important place for water birds. About 5,000 water birds visit Lake Biwa every year.