The Phong Nha cave, from which the name to the whole system and the park is derived, is famous for its rock formations which have been given names such as the "Lion", the "Fairy Caves", the "Royal Court", and the "Buddha". Phong Nha cave is 7729 meters long but tourists can only penetrate to a distance of 1500 meters, and it contains several
grottoes or chambers, including the Bi Ky grottoes. Its cave system features underground passageways and river caves filled with stalactites and stalagmites. The stalagmites that used to stand at the cave's entrance apparently inspired its name: Phong Nha means "Wind and Teeth". After flowing about 19 km underground, the Son river emerges from the mouth of this cave, draining a huge area of the
limestone mountains around Phong Nha. Phong Nha Cave is recognized by organizations such as the
British Cave Research Association for its geographic features, including an underground river, a large underground lake, and its entrance dimensions. The cave system contains extensive dry passages, sandbanks, reefs, and various stalactite and stalagmite formations. ==See also==