Nhi Thanh cave is located on Nhi Thanh street in Tam Thanh ward, Lang Son city, is part of the most famous relic complex in Lang country including: Nhi Thanh cave, Tam Thanh cave, Mac citadel and To Thi mountain. The cave is marked by thousands of years old magnificent stalactites, and is also one of the spiritual destinations attracting tourists in Lang Son city.