Explanation:

The Sundarbans delta is the largest mangrove forest in the world and is intersected by a complex network of tidal waterways, mudflats and small islands of salt-tolerant mangrove forests.  It lies at the mouth of the Ganges.
  The Sundarban Delta is situated on the border of India and Bangladesh, where the Ganges, Brahmaputra, and Mehgna rivers converge in the Bengal basin.
The area of Sundarbans is estimated in size at 10,000km2 (UNESCO). The area itself gets its name from the large number of Sundari (Heritiera fomes) trees in the region.
  Free of permanent habitation and almost 70% covered by mangrove forest, this massive area is home to more than 400 Bengal tigers - possibly the highest concentration on the planet.
  Accompanying the tigers are a plethora of other animals inlcuding a wealth of water birds, the fishing cat (Felis viverrinus), spotted deer (Cervus axis), crocodiles and snakes. Under the waters of the Sundarbans one can find the Ganges dolphin (Platanista gangetica), Indo-Pacific hump-backed dolphin (Sousa chinensis), Irrawaddy dolphin (Orcaella brevirostris) and finless porpoise (Neophocaena phocaenoides).
The Sundarbans National Park was inscribed in the UNESCO World heritage List in 1987 and the portion of the Sundarbans lying in Bangladesh was inscribed in 1997.