Tags: Cave.
Phong Nha Cave is a cave in Phong Nha-Kẻ Bàng National Park a UNESCO World Heritage Site in Quảng Bình Province Vietnam. It is 7729 metres long and contains 14 grottoes as well as a 13969 metre underground river. While scientists have surveyed 44.5 kilometres of passages tourists are only allowed to explore the first 1500 metres. It is the second biggest cave in Vietnam.
