Bac Son limestone block in the Karst area of Northeast Vietnam has an area of about 1,500 km2. Bac Son Son Mountain has an average altitude of 400 -700 m above sea level, belongs to a temperate climate zone, cool all year round, fresh air with an average annual rainfall of 1,380 mm. 2 seasons.
The process of karstification together with the conditions of topography, climate, hydrology and a number of other conditions have created for Lang Son Geopark a system of beautiful, massive, long limestone caves. There are many stalactites with many forms, most of which are preserved intact. In terms of structure, the karst mass located in Lang Son Geopark is a large convex complex divided into individual blocks with many cracks, facilitating the penetration of rivers and streams into the cave system.
