Cat Ba archipelago in the northern city of Hai Phong, officially recognised by UNESCO as a world biosphere reserve on December 19, 2004, has become a familiar destination for many tourists, especially those who are interested in ecotourism. The Cat Ba World Biosphere Reserve, located on Cat Ba Island, Cat Ba township, Cat Hai district, covers a total area of 26,240 ha with about 400 surrounding islets. Together with Ha Long Bay, it forms an interesting island-bay complex. The Cat Ba National Park is the nucleus of the biosphere reserve, with 9,800 ha of forest and 4,200 ha of sea. Cat Ba is one of the few areas that still maintain and preserve a diverse ecosystem, gathering all the characteristics of the tropical forests on the limestone islands, mangrove forests, coral reefs, seaweed beds, saltwater lakes in the middle of the mountain, and especially the intertwined system of caves, including those discovered not long ago. VNA Photo: Minh Đức