The Sundarbans are the largest littoral mangrove belt in the world .

Sundarbans mangrove forest is the largest in the world, and covers areas of India and Bangladesh for more than 80 kilometers in forming Sundarbans National park, declared a World heritage site  by Unesco. 
A third of this area is covered by water and marshes, as well Sundarbans since 1966 has been considered a sanctuary for wildlife because it is estimated that there live about 400 Royal Bengal tigers and more than 30,000 deer in this area. 
The forest lies at the feet of the Ganges and is spread across areas of Bangladesh and West Bengal, India, forming the seaward fringe of the delta. The seasonally-flooded Sundarbans freshwater swamp forests lie inland from the mangrove forests.
The forest covers 10,000 km2 of which about 6,000 are in Bangladesh. It became inscribed as a  site in Unesco World heritage 1997, but while the Bangladeshi and Indian portions constitute the same continuous ecotope, these are separately listed in the UNESCO world heritage list as the Sundarbans and Sundarbans National Park, respectively. 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 the eponymous Royal Bengal Tiger (Panthera tigris tigris), as well as numerous fauna including species of birds, spotted deer, crocodiles and snakes. It is estimated that there are now 500[citation needed] Bengal tigers and about 30,000 spotted deer in the area. Sundarbans was designated a Ramsar site on May 21, 1992. The fertile soils of the delta have been subject to intensive human use for centuries, and the ecoregion has been mostly converted to intensive agriculture, with few enclaves of forest remaining. The remaining forests, together with the Sundarbans mangroves, are important habitat for the endangered tiger. Additionally, the Sundarbans serves a crucial function as a protective flood barrier for the millions of inhabitants in and around Kolkata (Calcutta) against the result of cyclone activity. 
Sundarbans is home to many different species of birds, mammals, insects, reptiles and fish. It is estimated that there may be found more than 120 species of fish and over 260 species of birds and more than fifty species of reptiles and eight amphibians. Many tourists go there to see the Bengal tigers, saltwater crocodiles, leopards and snakes cobra. 
 Geographical data of Sundarban -Latitude: 25.7667
Longitude: 88.7167
Average Height: 34
Time Zone: Asia / Dhaka