Located in the north of Vietnam, in the Gulf of Tonkin, it is 120 kilometers long, an area of 1,500 square kilometers of emerald water, more than 2,000 islands and islets of karst stone with tropical jungles on its summits and caves which can only be accessed by water. On junk tours and kayak expeditions, visitors can navigate islands named after their shape, such as the Perro de Piedra and Tetera islets. In this region you can go diving, climbing and hiking, especially in the mountainous Cat Ba Nature Park. Its importance is such that in 1994 it was declared a World Heritage Site by UNESCO. It has also been considered, since 2011, as one of the Seven Natural Wonders of the World.