The land mass that rose from the sea bed from the siltation of two mighty rivers, the Ganges and the Brahmaputra, supports a thick mangrove forest that took root two million years ago. Unique in the world in many ways, it is our Sundarbans. Of course it was not where it is today. It spanned a huge area--from Lucknow in present day India to the North Bengal and Assam.

Chinese traveller Huen-Tsang visited India between 629 and 645 AD and explored the deep forests of the Sundarbans. He came to Pundrabardhana (Pabna or Rangpur) and mentioned the country was wet, fertile, and prosperous.

Emperor Babur first mentioned a specific animal of the Sundarbans-- the lesser Rhinoceros that was found in the Bengal Sundarbans.

From the time of the Mughals, Sundarbans lands were being leased out and cleared for habitation.

Today only its sad remnants remain in Khulna.

Even at the beginning of the British rule, the forest was spread over 43,252 square kilometres. When the British left India, it had shrunk to 37,813 square kilometres. Today, because of human encroachment, the one and only such place on the planet has shrunk to a mere 10,000 square kilometres – 6000 in Bangladesh and 4000 in India.

Its first map was drawn in 1929 by a British civil servant who dared to enter this formidable forest and listed its vast natural resources.

So why should we care about this amazing forest? Is it only because it is the home to the Bengal Tiger?

First, let's have a look at its rich biodiversity. "The price of the Sundarbans cannot be monetized," writes Bipradas Barua, Ekushey Padak winner writer and naturalist. "With the annihilation of the Sundarbans the first disaster will be revealed in the change in climate."

The forest offers a solid wall against cyclones and that is why when tropical cyclones Sidr and Aila hit the coast, loss of life was relatively lighter. The forest took the brunt of the storms saving human lives. Once it is gone or depleted, the coastal people will become vulnerable to cyclones which would be a frequent phenomenon because of climate change.

"In Bangladesh, the Sundarbans is possibly the last hope for the survival of any unique and great population of wildlife because all other types of forests such as the Sal and mixed forests in the hills have virtually become barren," writes Reza khan, an eminent wildlife conservationist.

The Sundarbans is a living museum of biodiversity. It has 50 species of mammals, 320 species of birds, 50 species of reptiles, eight species of amphibians and about 400 species of fish. Nowhere in the country such a wide variety of flora and fauna are found, many of them globally endangered.

Those who enter the forest only hope to see Bengal Tigers, the apex predator of the forest. Unfortunately, the number of this magnificent animal has shrunk to only 105 in this part of the forest from an estimated 500 in a span of only one decade.

However unaware the visitors are, every inch of the forest contains some kind of interesting living being. As you step on the soft mud, you are likely to step on mudskippers, crabs or say, the non-venomous dog-faced water snake. You will find red fiddler crabs with one giant arm scurrying sideways.

Butterflies, wasps, bumblebees, flies, dragonflies and so many other winged insects buzz around you. Honeybees are the most important insects that make huge honeycombs from where honey is commercially collected by the Mouals.

 Spiders, scorpions and centipedes crawl about the forest.

Among the invertebrates, the most important commercial species are shrimps, prawns and lobsters. Crabs are collected in commercial scale.

Through the Meghna estuary, enter schools of hilsas. A major hilsa passageway is through the forest. The most important commercially exploited fishes are the hilsa, loitya, vetki, lakkha, pomfret and many other commercially valuable species.

Sundarban is also home to several important reptiles including the saltwater crocodile, sea turtles, including the green turtle and Olive Ridley's -- and the critically endangered Batagur turtles.

Some 13 globally threatened and near-threatened bird species live in the Sundarbans.

"For the three of the 13 birds of global conservation concern -- masked finfoot, brown-winged kingfisher and mangrove pitta – the Sundarban may easily be the largest and the safest home in the world," writes Enam Ul Haque, an eminent bird specialist.

"Masked finfoot is an important bird found in the forest," writes Sayam U Ahmed, conservation biologist working on threatened species conservation in Bangladesh and abroad. "Only a thousand or even less number of mature masked finfoots are left in the world and our Sundarban supports a considerable number of them."

Critically endangered species like the river terrapin and the white-rumped vulture or the endangered fishing cat and the globally threatened raptor Pallas's fish-eagle live in this forest.

King cobra and Burmese python listed as vulnerable by the IUCN are also seen in the forest. And it is the only place on earth where both the Ganges River dolphins and Irrawaddy dolphins live together.

 But there is more. The mangrove forest offers a perfect spawning place and habitat for fish.

The Sundarbans support roughly 196 species of fish, 49 percent of the recorded species. A large number of people depend on this fish. About 25,000 registered fishing boats harvest fish from the Sundarbans and its adjacent bay. The annual catch from the forest water bodies is estimated to be 3,000 tonnes of fish and 18,150 tonnes of crustacean.

However, in Dublar Char alone, about 18,000 tonnes of fish is caught from the bay. Besides 110 million crustaceans is collected from the creeks of the forest.

The forest is already tired in its battle for survival, it cannot take another blow. For millenniums, the forest has withstood nature's fury, during the reign of Mughal emperor Akbar and later during Raja Pratapaditya's rule, it withstood severe cyclones and those events have been followed by many similar calamities.

It withstood human invasions – those of the Maghs and the Portuguese pirates.

But today, it faces another kind of battle – that forced upon it by a desire for development. It may as well be its last battle against pollution and encroachment.