Sundarbans of Bangladesh is one of the wonders in the world.

The Sundarbans is the largest single block of tidal halophytic mangrove forest in the world.The name Sundarban can be literally translated as "beautiful jungle" or "beautiful forest" in the Bengali language (Sundar, "beautiful" and ban, "forest" or "jungle"). The name may have been derived from the Sundari trees that are found in Sundarbans in large numbers. Alternatively, it has been proposed that the name is a corruption of Samudraban or Chandra-bandhe (name of a primitive tribe). But the generally accepted view is the one associated with Sundari trees.
The Sundarbans are the largest littoral mangrove belt in the world, stretching 80km (50mi) into the Bangladeshi hinterland from the coast. The forests aren't just mangrove swamps though, they include some of the last remaining stands of the mighty jungles which once covered the Gangetic plain. The Sundarbans cover an area of 38,500 sq km, of which about one-third is covered in water. Since 1966 the Sundarbans have been a wildlife sanctuary, and it is estimated that there are now 400 Royal Bengal tigers and about 30,000 spotted deer in the area.
The park is also home to sea gypsy fishing families who catch fish using trained otters. To see this pristine environment, you need to get a permit from the Divisional Forest Office in Khulna. With permit in hand, it's possible to hire a boat from Mongla or Dhangmari to get you to Hiron Point. From Hiron Point you will have to hire a guide to take you into the park.Sundorbon is the largest mangrove forest in the world. It lies across areas of Bangladesh and West Bengal, India. Its a cluster of islands with an approximate area of 6000 sq. km. forming the largest block of littoral forests.It is estimated that there are now 400+ Bengal tigers and about 30,000+ spotted deer in the forest!UNESCO has decleared the Sundorbon a world heritage site that it offers splendid opportunities for tourism.It's beauty lies in its unique natural surrounding. The Sundorbon is intersected by a complex network of tidal waterways, mudflats and small islands of salt-tolerant mangrove forests, and presents an excellent example of ongoing ecological processes. Thousands of meandering streams, creeks, rivers and estuaries have enhanced its charm. Sundarbans meaning beautiful forest is the natural habital of the world famous Royal Bengal Tiger, spotted deer, crocodiles, jungle fowl, wild boar, lizards, theses monkey and numerous species of birds. Migratory flock of Siberian ducks flying over thousands of sail boats loaded with timber, golpatta (round-leaf), fuel wood, honey, shell and fish further add to the serene natural beauty of the Sundarbans. It is estimated that there are now 400+ Bengal tigers and about 30,000+ spotted deer in the forest!AREANearly 2400 sq. miles or 6000 sq. km.FOREST LIMITSNorth-Bagerhat, Khulna and Sathkira districts : South-Bay of Bengal; East-Baleswar (or Haringhata) river, Perojpur, Barisal district and West-Raimangal and Hariabhanga rivers which partially form Bangladesh boundary with West Bengal in India.Sundarbans is home to many different species of birds, mammals, insects, reptiles and fishes. Over 120 species of fish and over 260 species of birds have been recorded in the Sundarbans. The Gangetic River Dolphin (Platanista gangeticus) is common in the rivers. No less than 50 species of reptiles and eight species of amphibians are known to occur. The Sundarbans now support the only population of the Estuarine, or Salt-Water Crocodile (Crocodylus parasus) in Bangladesh, and that population is estimated at less than two hundred individuals.I like to say you with cheerfulness that Mangrove Sundorbon is selected one of 7wonder place in world. It is situated in country of Bangladesh at Bagerhat area and fortunately, I live in that district. So I am very happy for it. Sundorbon is the biggest Mangrove forest in the whole world. The Royal Bengel Tiger lives in this Jangle. And many other animals, birds and trees are available in there. Nobody can enter in this jangle without gun. This is very very danger place for human. A lot of wild animals move there.