Ma Phuc Pass

The name of Mã Phục Pass is already a story.

Mã Phục is a Sino-Vietnamese name, and it means a kneeling horse. Local people tell a legend about it, and the People's Army newspaper has written it down. In the 11th century, the leader Nùng Trí Cao led his people against Song forces. The Song were the dynasty then ruling China. On one trip back from patrolling the border, he came to the area now called Quốc Toản. There his horse could go no farther on the high, winding, steep pass. From then on, the pass was called Mã Phục.

This is a local legend. But the shape of the pass could well make a horse kneel for real.

Mã Phục Pass is more than 3.5 kilometers long and lies about 700 meters above sea level, winding between two tall ranges of limestone mountains. It is a geological heritage site in 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. The province of Cao Bằng listed the pass in its inventory of heritage sites in 2024. UNESCO recognized the geopark in 2018. It is known for its chains of limestone, its tropical karst, its caves and underground rivers, and Bản Giốc Waterfall. Mã Phục is the first stop on the geopark's eastern route. The route goes on to the Mắt Thần Núi area, the craft villages and Ngườm Ngao Cave.

The most interesting thing here is not the view of the pass. It is what lies at its foot. The People's Army newspaper quotes Trần Văn Tân, director of the Institute of Geological Sciences and Resources, describing round, blue-black rock meeting white limestone. That round, blue-black rock is pillow basalt. It forms when volcanic lava erupts under the sea and meets cold water. The lava cools very fast and sets into round lumps piled on top of one another. So hundreds of millions of years ago, this land was not forest or hills. It was the seafloor, with volcanic activity beneath it.

The landscape seen today, those grand limestone ranges, is the result of a process so long that ordinary imagination can hardly grasp it.

Mã Phục is a good place to understand the karst landscape of Cao Bằng. The limestone mountains on both sides of the road, the valley below and the wide sky above are all the work of limestone worn away by rainwater and groundwater over millions of years. Karst is not a kind of rock. Karst is a process, and Cao Bằng is one of the places in Vietnam where that process shows most clearly.

Standing here, looking down on the tiers of valleys and up at the limestone peaks, you can see the result of 500 million years of Earth's history directly. It is not in a museum or on a screen, but right in front of your eyes.

At the foot of the pass, blocks of blue-black pillow basalt lie right against white limestone, like two worlds touching hands. Above, the limestone peaks rise sharp against the sky. And through the middle, the pass winds like a thin thread, joining the two sides of a landscape that was made before the Earth had any green plants.