The Legend of Trentren Vilu and Caicai Vilu is the "legend of the geography and origin of the Chiloean archipelago, and mountains of southern Chile", which was caused by a fierce battle between two mythical snakes, Trentren Vilu (trentren="related with the earth", vilu="snake") and Caicai Vilu (Caicai="related with the water", vilu="snake").