India and Bangladesh
Stretching 3,800 square miles across India and Bangladesh, this cluster of low-lying islands in the Bay of Bengal is famous for its unique mangrove forest. One of the largest in the world, it’s home to the rare Bengal tigers, saltwater crocodiles, chital deer, and Ganges river dolphins. Unfortunately, ongoing pollution, deforestation, and overfishing are causing its coastlines to erode and killing off its mangroves. UNESCO estimates that if there is a 45-centimeter (17.7-inch) rise in sea level, 75% of the Sundarbans mangroves will be lost, and with it the many animal, plant, and human lives that depend on it.
Insider Tip: Visiting the Sundarbans National Park can only be accessed by boat, and permits are required. Don’t go expecting to spot a Bengal tiger (they’re usually roaming within the park's tiger reserve which is not open to tourists) but to appreciate its raw, pristine beauty, and very likely some crocodile sightings.