The hook
The largest mangrove forest on Earth — shared with Bangladesh, which holds the bigger share — a tidal maze of channels and silt islands where the Ganges meets the sea — and the only mangrove forest anywhere that holds a population of tigers, which here swim between islands and are almost never seen.
01Why it's worth it
The Sundarbans is a landscape without solid ground: some 10,000 square kilometres of mangrove split between India and Bangladesh, cut by tidal creeks that fill and empty twice a day, with roots standing out of the mud like fences. You travel it by boat, slowly, and the pleasure is the forest rather than a checklist — kingfishers, crocodiles, macaques, otters, and the constant sense that the land is provisional. Bengal tigers live here in real numbers, and are famously hard to see; guides will tell you honestly that a sighting is luck, not itinerary. Trips run cheaply out of Kolkata, and the seafood is excellent.
Two honest notes. It is genuinely disappearing: sea-level rise, cyclones and upstream water diversion are eroding islands, salinating soil, and displacing the people who live here — this is one of the clearest places on Earth to see climate change as a present-tense event rather than a forecast. And the tigers here have a documented history of attacking people working the waterways, which is why access is restricted and you stay on the boat.
02How to experience it
Book a two- or three-day boat trip from Kolkata (all-inclusive packages are inexpensive and cover transport, food and lodging). Come November to February. Set expectations away from tigers and toward the forest, the birds and the tidal channels. Bring binoculars.
From the locals
Indian travellers push it precisely because it's overlooked and precarious: "if you are going to India, consider seeing the Sundarbans mangrove forest south of Kolkata — it is beautiful, has amazing seafood, and is a natural Bengal tiger habitat," one wrote, adding the part that gives the trip its urgency: "it is also quickly disappearing due to climate change and may not be around in the next" decades. On cost, another: "there are some very inexpensive all-inclusive tours that leave from Kolkata — I went for about 60 USD on a two day, one night tour, and that included food, transportation, entrance to the reserve, day and night safari, and very comfortable lodging."