In the nice day, travelling on boat, you can see the bottom of the river with the range of stone and the flock of fish swimming and playing under the rock. The most special thing is the color of water which divided into many different parts, one in the jade color, one in blue, one in the mixture of green and yellow. That is really fantastic!

According to the officers in Phong Nha-Ke Bang national park, the water has many different colors because along two banks of the river are the high cliffs of the limestone-mountain, the green tree of forest, and in the bottom of river is the green alga.

From the crossroad of Chay River toward about 2km is the gate into Dark Cave. This is one cave in the Phong Nha-Ke Bang cave system, which was researched in 1990 and 1992 by the English explorers.

Now, Chay River has been used as a sightseeing tour in the 5-7km. The first tour starts from Phong Nha cultural and tourism center to Nuoc Mooc stream, the second one from Phong Nha and Tien Son cave to Nuoc Mooc stream, the third one from Nuoc Mooc stream in Ho Chi Minh path to Tro Mong and sailing to Dark Cave. All three tours start from the upstream of Chay River.

Crossing Chay waterfall is Nuoc Mooc stream where exist lots of beautiful rock banks. The stream flows through a flat and large place; therefore, this is also an ideal place to camp or relax and enjoy the scenery surrounding.

Sailing along Chay River, you can luckily sea many types of fish (about 82 types of fish living on this river). Perhaps, the most interesting activity when participating in a tour on this river is the moment when we are waiting for buying shrimp from the local fishermen and celebrating a simple party on boat.