Non Nuoc Cao Bang Geopark

More than 500 million years. That is how much time the rocks around this corner of northern Vietnam have weathered.

The area that is now Cao Bằng was once the floor of a sea. Then volcanoes erupted under the water and made a special kind of rock, shaped like round balls stacked on top of one another. Geologists call it pillow basalt. Later the sea drew back and the land rose. For tens of millions of years, rain and groundwater wore away the limestone, carving out caves, rock towers, valleys, lakes and holes that pierce right through the mountains. Then people came. They built villages, learned crafts, grew rice, made incense, forged iron, wove cloth and wrote their history.

All of this lies inside the area known as the Non Nước Cao Bằng UNESCO Global Geopark. A UNESCO Global Geopark is an area with landscapes of international geological importance, managed for protection, education and sustainable development.

UNESCO granted the title in April 2018. In 2026, after its second review, the geopark received a green card once more, and the title was extended for another four years. A green card is UNESCO's sign that a geopark still meets its criteria. The geopark is a whole region rather than a single destination. It covers more than 3,683 square kilometers, spread across 36 communes and wards of Cao Bằng province.

Within it lie more than 130 sites of geological heritage. They range from fossils of ancient coral to volcanic rock, from karst towers to underground caves, and from lakes to the boundaries between layers of geological time. And above all those layers of stone is life itself: the craft villages, beliefs, languages and music of many different peoples.

On the eastern route, the first stop for many groups is Mã Phục Pass. Its name is tied to a local legend about Nùng Trí Cao, a leader of the 11th century. The story says his horse could go no farther on this high, steep pass. Mã Phục means the kneeling horse. That part is folk legend, but the geology here is very real. At the foot of the pass, blue-black pillow basalt meets white limestone. It is the trace of an undersea volcanic eruption about 260 million years ago.

Farther on is the mountain known as Mắt Thần Núi, the magic eye of the mountain. The Tày call it Phja Piót, which means the mountain with a hole. The Tày and the Nùng are two peoples of northern Vietnam with closely related languages and similar cultures. A round hole more than 50 meters across runs straight through the body of the mountain. It sits in the area of the Thang Hen lake system, where 36 natural lakes connect with one another. In the dry season, a grassy valley spreads below the mountain. In the rainy season, the water rises and the whole valley turns into a lake. In 2021, the Ministry of Culture, Sports and Tourism ranked the mountain a national scenic site.

Leaving the stone mountains behind, the eastern route passes through three remarkable craft villages of the Nùng An people. Dìa Trên village makes giấy bản, a handmade paper used in folk beliefs and community rites. Phja Thắp village has made incense for more than 100 years. Its makers use natural materials such as cinnamon, honey locust and bầu hắt. And Pác Rằng village, in Quảng Uyên commune, is known for a blacksmithing craft. In 2019 that craft was inscribed as national intangible cultural heritage. The sound of hammers on iron anvils here is nothing new. It has rung out for many generations.

Then comes Ngườm Ngao Cave, in Đàm Thủy commune. It runs for more than 2,000 meters and has three main entrances. Inside is a world of stalactites and stalagmites, of stone curtains and shapes with names of their own. There is a golden waterfall and a silver waterfall. There is a pillar that holds up the sky, an upside-down lotus and a set of terraced fields.

On the way to the cave, the road passes Khuổi Ky stone village. This is a Tày village of 14 stone stilt houses, on about 10,000 square meters of land. The houses lean their backs against the mountain and look out over Khuổi Ky Stream. The Tày of Trùng Khánh hold a belief that honors stone. So stone is not only in the walls. It is also in the stoves, the grinding mills, the fences and the foundations. The Tày here link these stone houses with the time when the Mạc dynasty came up into these mountains and built citadels, from 1594 to 1677.

The last stop on the eastern route is Bản Giốc Waterfall, with the Trúc Lâm Bản Giốc Pagoda close by. The two sites lie about 500 meters apart.

The finest thing about traveling in this geopark is seeing how everything connects, more than reaching as many sites as possible. Geology makes the landscape. The landscape draws people in. People build villages, learn crafts and grow a culture. And all of it lives together in a heritage region more than 500 million years old.

Underfoot is volcanic rock that once lay deep on the floor of the sea. Ahead, a round hole runs straight through the body of a mountain, letting a whole patch of sky shine through. Somewhere in a village, a hammer rings on an iron anvil, as steady as it has sounded for generations. And the scent of cinnamon and honey locust drifts on the wind.

Cao Bằng is a place where stone tells a story, and people are still writing the next chapter of it.