3 – 4 hours
Phong Nha Cave, although it had been used previously, the cave was recorded as officially discovered in 1899. In 1990 a group of British scientists joined Hanoi University on an expedition inside the cave with the mission to fully explore the cave and document it. Several expeditions were organized and the group successfully discovered 8,821 meters of cave. The cave was found to have a maximum height of 50 meters and a maximum depth of 83 meters. This finding of this expedition and survey was the reason for opening it up for tourism in 1995. The extremely large subterranean river system runs through the entire cave, however, there are some large dry chambers in the cave which the water doesn’t reach anymore. The cave is divided into three different sections; each section is home to different animal species and there is a big difference in temperature.