Tadlak Lake

Tadlac Lake, also colloquially known as Alligator Lake, is a freshwater volcanic crater lake located in Barangay Tadlac, in the municipality of Los Baños of Laguna province in the Philippines. The lake-filled maar is located along the southern shore of Laguna de Bay, the largest lake in the country, with Alligator Lake protruding out of the shore of the larger lake. If not for its slightly-elevated crater rim, Alligator Lake would be wholly engulfed by Laguna de Bay.The crater lake is one of the maars of the Laguna Volcanic Field.

Source: Wikipedia