Phong Nha Caves are the complex of 14 grottoes situated in a region of limestone mountains in Ke Bang National Park. Phong Nha Cave have a total length of 7,729 m. Phong Nha Cave was listed as a World Natural Heritage Site in July of 2003 by Unesco. The Cham People has used Phong Nha Cave as Buddhist sanctuaries in the 9 and 10 centuries. Visit the cave, you will have a chance to explore the remain of Cham altars and inscriptions inside the cave.