Dark Cave is one of the prominent caves in Phong Nha - Ke Bang National Park, located about 50km from the center of Dong Hoi City. The cave is situated right on the Chay River, near En Cave and Son River, creating a magnificent cave system amidst the pristine nature of Quang Binh.

Geologically, Dark Cave is a karst cave, formed about 400 - 500 million years ago through the weathering and erosion of limestone by water. The cave is approximately 5,258m long, featuring many small branches and underground lakes inside. True to its name, Dark Cave receives almost no natural light, creating a mystical and untouched atmosphere. The stalactite system inside the cave still retains its original beauty with many unique shapes.
The mineral mud in Dark Cave was formed from the accumulation of natural minerals, mainly through millions of years of limestone weathering. Underground streams flowing through geological layers carry precious minerals such as calcium, magnesium, iron, zinc, sodium..., combined with organic sediments, creating a fine and nutrient-rich mineral mud layer.



