Description : Sundarbans, seen from the Ganga River. The Sundarbans delta is the largest mangrove forest in the world. It lies at the mouth of the Ganges and is spread across areas of Bangladesh and West Bengal. The Sundarbans is intersected by a complex network of tidal waterways, mudflats and small islands of salt-tolerant mangrove forests. The area is known for its wide range of fauna. The most famous among these are the Royal Bengal Tigers, but numerous species of birds, spotted deer, crocodiles and snakes also inhabit it. Bangladesh.