The Sundarbans National Park, a UNESCO World Heritage site, is the world’s largest mangrove forest. It stretches 50 miles across Bangladesh and West Bengal, and is made up of primeval jungles and marsh areas filled with fascinating wildlife. Over 400 Royal Bengal tigers live within the Sundarbans, along with a wide mix of flora and fauna. Tourists come here to spot leopards, saltwater crocodiles, various primates, insects, fish, birds, reptiles, and mammals. Booking a guided tour is advised because the forests can be tricky to navigate. This is a protected reserve, so entry permits are required.