This is a beautiful lagoon is created as the Nam Don River emerges from a cave below a large cliff 300m tall. You can ride a boat into the cave for about 20m then the river disappears into extensive underground tunnels. The cave continues for 3km into the mountain. A French survey team in 1998 discovered a new genus of blind cave fish 150m inside the cave at a depth of 23m. This fish is small, pale and has no exterior eyes, which would be useless in this completely dark environment.
Outside the cave local fishermen sometimes place nets in the pool so be careful when swimming. You can enter the cave by swimming or ask local fisherman to take you in by canoe. During the wet season the river rises considerably and the Nam Don River becomes navigable by boat. This location is a great picnic spot or swimming hole, with a shady forest near the cliffs that provides an ideal resting place for walkers. On the other side of the Nam Don River is a small Buddhist shrine.