The Sundarbans is a natural region in southern Bangladesh and the extreme southern part of the Indian state of West Bengal in the vast river delta on the Bay of Bengal. It is the largest single block of tidal halophytic mangrove forest in the world. The Sundarbans covers approximately 10,000 square kilometres most of which is in Bangladesh with the remainder in India. The Sundarbans is a UNESCO World Heritage Site. Sundarbans South, East and West are three protected forests in Bangladesh.