British and Vietnamese speleologists have found 25 more caves and grottos with a total length of 12 km in the buffer zone of the Phong Nha-Ke Bang natural heritage site in central Quang Binh province. Quang Binh province, on April 11, announced the discovery by the experts after a month of survey. Information collected in the survey showed that Quang Binh has great potential in its caves and grottos, including the longest Southeast Asian systems of caves with mysterious primary beauty in limestone mountains. Quang Binh intends to tap into this potential to further develop the tourism industry, especially tours of grottos, caves, and the Phong Nha-Ke Bang National Park, which has been recorgnised as a world natural heritage site, and its buffer zone. The experts, from Britian and the Hanoi Natural Science College of Hanoi National University, also discovered a 170m-deep hole in Viet Nam's longest grotto.