The Nhi Thanh Cave, about 700 m away from the Tam Thanh Cave, was discovered in the 18th century by Ngo Thin Sy, military commander of the Lạng Sơn garrison, whose poems have been inscribed at the entrance to the cave.
The Nhi Thanh Cave was discovered in the 18th century by Ngo Thin Sy. This was about 700 m away from the Tam Thanh Cave. Ngo Thin Sy was military commander of the Lạng Sơn garrison, whose poems have been inscribed at the entrance to the cave.