Phong Nha and Kho cave are only two among 300 caves and caves in the natural preserve zone of Phong Nha – Ke Bang, which is so-called “kingdom of caves”. Tien Son entrance is about 1,000 m from Phong Nha cave on the height of 200m.
Tien Son is located in the Limestone Mountains of Ke Bang of Son Trach commune, Bo Trach district. According to Thai Van Kiem in the book “Vietnam landscape”, Tien Son cave was found in April 1935 by a local man. When it was newly discovered, Tien Son cave was called Tien cave (fairy cave) for its mysterious beauty. Later, the Phong Nha cave was found and people call this Kho cave (dry cave).
The landscape in Tien Son cave is said to be the P’eng lai land. There are thousands of stalactites in the cave with different colors. The dome is high with the emerging of porphyry that has the colors like silver of gold. The pillars of marble make people being delighted like being in the Thien Cung or Thuy Cung (palace under the sea).
Tien Son has different features from Phong Nha for being the flagstones and pillars of stone that are sound resonant. When people knock on them, there would be strange sounds like the gongs and drums from the very deep part of the earth.
According to the research of the discovery group of British association of Caving, Tien Son cave is created since tens of millions of years when there was a water line flow through the mountain, and it carve the cave into empty mountain of Ke Bang. Then due to the topography constructing, this part of mountain was raised up or collapsed and the blocks of stone tumbling to block, the water line and Tien Son cave was created on the above. The part which has the underneath river is Phong Nha cave.
According to the surveying, though these two caves are next to each other, but there is no connection between these two. Tien Son cave is 980m long, and from the entrance gate, there is a chasm of 10m deep and an underneath stock ground of 500m long, which is quite dangerous. People can just visit 400m long from the entrance gate.
People around this place said that this is the beautiful landscape with the objects that could be the relics of ancient people in the flat area in front of the entrance. That would even make the Tien Son cave more mysterious and attractive.