A shroud of mystery and danger looms over the Sundarbans National Park, the largest mangrove forest in the world. It's an enormous network of interconnecting waterways, stretching inland for about 80km from the Bay of Bengal, and it's home to around 400 Royal Bengal tigers, the largest single population of tigers in the world.
This is truly wild terrain, and a three- or four-day boat trip into the heart of this magnificent part of south Asia often ranks as the No 1 highlight of a trip to Bangladesh.
Tigers here are unusually small - sometimes only half the size of those found in central India and Nepal - but they have a fearsome reputation for being man-eaters. In fact, the Bangladesh region of the Sundarbans suffers the highest levels of humans killed by tigers in the world. According to Bangladesh Forest Department figures, since 1986 an average of 20 to 30 people have been killed by tigers here each year, the vast majority of whom are local fishermen (44%), woodcutters (36%) or honey collectors (18%).
The Sundarbans begins about 5km southwest of Mongla along the Pasur River, and covers an area, split 60/40 between Bangladesh and India, of about 10,000 sq km. About one-third of the total area of this forest is covered in water - river channels, canals and tidal creeks varying in width from a few metres to a few kilometres. The land is constantly being reshaped by tidal action, and cyclones also wreak their havoc.
The ecological balance of these largely impenetrable forests is extremely delicate and influenced greatly by tidal shifts that affect the salinity, and hence the growth rates, of the surrounding vegetation. The eclectic inhabitants of the Sundarbans range from deer, pigs, crocodiles and crabs to the mighty Royal Bengal tiger. The Divisional Forestry Office supervises activities to protect the delicate ecological balance and botanists, zoologists, environmentalists and conservationists around the world keep eager eyes on this ecological repository.
The dry season, November to April, is the most popular season for visiting the Sundarbans. April is a particularly interesting time to visit as it coincides with the honey-harvesting season. Between December and February there is also the chance to venture out to the Swatch of No Ground, a deep-water canyon a short way offshore from the Sundarbans, where it's sometimes possible to go whale- and dolphin-watching.