The document discusses the Sundarban mangrove forests located in India and Bangladesh, which form the largest mangrove ecosystem in the world along the Ganges and Brahmaputra river deltas. It notes that the Sundarban Biosphere Reserve contains the only mangrove forests that are home to the Bengal tiger, and that the reserve supports a wide variety of flora and fauna including estuarine crocodiles, deer, monkeys, eagles, snakes, and dolphins. The document also mentions that the Sundarban forests are important economically and culturally, and have been designated as a UNESCO World Heritage Site.