Chay River - Dark Cave (Quang Binh): Unique from its natural value to captivating experiences

Chay River - Dark Cave is considered a tourist route for exploring and experiencing the peaceful and poetic beauty of the wondrous nature, with a new and extremely attractive type of tourism in Quang Binh's tourism industry.

Although Dark Cave isn't as spectacularly beautiful as other caves, venturing deep inside allows visitors to admire its unique, pristine beauty. What visitors particularly enjoy is relaxing in the mud bath within the cave itself. The mineral mud in Dark Cave is 100% naturally formed and contains a high concentration of trace minerals with amazing health and skin benefits. Enjoy moments of relaxation immersed in nature, experience river activities such as ziplining across the river (400m long), short ziplining, adventurous bridge jumping, kayaking, taking photos on the floating raft, pyramid, and inflatable floats..., and savor traditional local dishes along the picturesque Chay River.

The romantic Chay River

The Chay River is one of the tributaries of the Son River. The waterfall is named Chay because the sound of the water resembles the pounding of a pestle. Although only about 10km long, the Chay River boasts many beautiful rapids and possesses diverse biological value with many aquatic animal species characteristic of Phong Nha - Ke Bang National Park, including the spotted eel and the spotted sardine, both listed in the world's Red Book of endangered species.

Dark Cave, discovered in 1990, is nearly 6,000m long and 80m high. It still retains its pristine, mysterious beauty due to the lack of artificial lighting. The cave remains unspoiled, with thousands of stalactite columns in diverse and unique shapes, and serves as a habitat for many animals such as bats and swallows. Notably, the cave entrance is also a refuge for the Ha Tinh langur – one of Vietnam's endangered primate species. Due to its location right next to the river and high humidity, the stalactites in Dark Cave are covered with a large amount of moss, creating its distinctive green color.

The Chay River nestles beneath majestic limestone mountains, flowing silently alongside ancient trees, then meandering through alluvial plains and cornfields in the verdant highlands. In some places, the riverbed reaches a depth of twenty meters, its gentle, romantic flow and clear, emerald-green water creating a picturesque landscape.

The river's unusually blue color gives visitors the feeling that no other river is as blue. Some researchers explain this by the erosion of the limestone mountains and the dissolution of calcium over millions of years, resulting in the perpetually blue water. However, others suggest that a type of algae bacteria feeding on the river's limestone produces nitrogen, making the water blue. It's unclear which theory is correct, but only by traveling along the Chay River can one truly appreciate its color, a shade even bluer than the sky. In different sections of the river, the water displays various hues: emerald green, green, yellow…

The river is emerald green.

The riverbanks are bordered by countless limestone banks. The flowing water, since time immemorial, has sculpted the limestone into strikingly unique "architectures." In the morning, the ancient fig trees reflect their beauty in the river, creating a scene as picturesque as a traditional ink painting. Beyond its beauty, the Chay River also harbors one of the most important fish communities in Phong Nha-Ke Bang National Park. Species such as the spotted catfish, the spotted eel, the spotted sardine, and dozens of other marine species live here, making this river, flowing through the mountains and forests of the Heritage site, truly unique. Two species listed in the world's Red Book of endangered species, the spotted eel and the spotted sardine, live here, astonishing ichthyologists worldwide.

Besides admiring the majestic mountain ranges typical of Phong Nha - Ke Bang National Park's topography and the cornfields, visitors also have the opportunity to experience the cultural life of the local people in ancient villages along the river such as Ha Loi, Na, Phong Nha, Tram, Me, Chay Lap…

In September 2014, the Phong Nha - Ke Bang National Park Management Board built a zipline system at the Chay River - Dark Cave boat dock. During the 2015 Quang Binh Cave Festival, representatives from the Vietnam Record Organization directly presented the certificate for this project as "the longest zipline with two cables in Vietnam." This is the only and first-of-its-kind project in Quang Binh, attracting a large number of visitors, especially foreigners.

Zipline on Chay River - Dark Cave

The highlight here is the zipline – the free-swinging activity. This activity includes two forms: a 400m zipline from the observation deck to the entrance of Dark Cave and a shorter zipline from the shore to the middle of the river, then a freefall under the Chay River. In just over a minute, tourists feel like they are soaring through the air on the journey from the observation deck to the entrance of Dark Cave.

It is thanks to the Dark Cave that scientists learned that the Ke Bang limestone massif originated from an ancient ocean. Ancient tectonic movements raised the seabed, and billions of shellfish died, creating the Ke Bang limestone massif, a World Natural Heritage site today. The Dark Cave also provides the most accurate specimen of a completely new crab species in the world, whose specimen is currently on display at the Singapore Natural History Museum.

The deeper you go into the cave, the more easily you can feel the coolness emanating from the rocks. Here, visitors need to be equipped with headlamps, life jackets, and adhere to certain regulations such as not bringing shoes, food, or foreign objects. Visitors will have an incredibly interesting experience bathing in natural mud or swimming in the cool Thuy Tien and Bong Lai lakes. Especially, visitors can immerse themselves in the pure, thin mud formed and refined by the limestone mountains. With a 15-minute session, visitors are often advised to limit the use of creams to preserve the natural mud layer.

Enjoy a mud bath in Dark Cave.

The greenery on the stalactites in Dark Cave is a novel and astonishing discovery for visitors. Why plants can thrive here is a fascinating question, and the answer leads to further interesting research. It's a legendary story of plants adapting to the harsh environment. Just behind the cave entrance is a giant stalactite column, its surface exposed to sunlight. This sunlight stimulates humidity and creates conditions for moss and algae to grow, allowing fern seedlings to attach and thrive. But where these plants "gave legs" to move into the cave is a story researchers have recently discovered. It was the wind that carried the fern seedlings into the nooks and crannies of the ancient stalactites.

A trip to the Chay River and Dark Cave not only offers visitors moments of relaxation but also provides those who enjoy exploration with a wealth of useful knowledge about the geology and biodiversity of Vietnam.

The Chay River and Dark Cave are an ideal and unique choice, offering visitors a wonderful and exciting experience.

Currently, the Phong Nha - Ke Bang Tourism Center is offering unique tour programs for this tourist destination.