Phong Nha CaveThis cave, from which the name to the whole system and the park is derived, is famous for its rock formations that have been given names such as the “Lion”, the “Fairy Caves”, the “Royal Court”, and the “Buddha”. This cave is 7729 m long, contains 14 grottos, with a 13,969 m-long underground river. The scientists have surveyed 44.5 km of grottos in this cave so far, but tourists can only penetrate to a distance of 1500 m.Paradise cave Thiên Đường “Paradise” Cave is a newly found cave in this area. Prior to the discovery of Sơn Đoòng cave, it was regarded as the largest and longest cave in Phong Nha-Kẻ Bàng. At 31.4 km long, Thiên Đường cave is longer than Phong Nha cave, previously considered the longest cave in this national park. The height can reach to 100 m and 150 wide. The limestone formation is also more spectacular than that of Phong Nha Cave.