Lake Letas is a volcanic crater lake on the island of Gaua that at 19 square kilometers in area and a maximum depth of 119 meters is the largest freshwater system in Vanuatu and the Pacific. The lake and its outflowing river accommodate a diversity of freshwater prawns, fish, and eels; and supports an ecosystem with a diverse and regionally-specific range of flora and fauna, including the swamp palm, the rare green palm lorikeet and royal parrotfinch, and many endemic plants and birds. The region is also a cultural monument for the native people of Gaua.