The Sunderban forest lies in the vast delta on the Bay of Bengal formed by the confluence of the three rivers. It is the largest single block of tidal mangrove forest in the world. It is a generally accepted view that the name Sunderbans has been derived from the Sundari trees that are found large numbers. It became a UNESCO World Heritage site in 1997. The area is known for the Royal Bengal Tiger as well as numerous fauna including species of birds, spotted deer, crocodiles and snakes.