Description : Respiratory roots (pneumatophores) of Mangrove trees along the edge of a canal in Sundarbans, the largest mangrove forest in the world. Khulna, Bangladesh. March 28, 2009. A UNESCO World Heritage Site, the area is known for its wide range of fauna, including 260 bird species, the Royal Bengal tiger and other threatened species such as the estuarine crocodile and the Indian python.