Doi Cave is referred to by locals in the region as ‘Ca Khao', which means a bat. It is 930 metres (m) in depth with an average height of around 60m to 80m, and is located in Lung Rum Village, of Dong Loan Commune, in Ha Lang area, Cao Bang Province. The cave is hidden under the forest foliage and rocky edges that are easy to totter up.

Standing in front of the cave, tourists can feast their eyes on the magnificent natural scenery. The sunlight slithers through the foliage and flocks of butterflies hover above the newly blooming wild flowers. Far away are the traditional stilt houses of the Tay and Nung people.

The cave includes 3 chambers which are separated by cliffs. The first one has colorful and unique stalactites and many small lakes. The second one has stalactites with mountains, terraced fields, gold and silver falls shapes. The third one is in semicircular shape with many giant yellow stalactites like stone pillars proping up the ceiling of the cave.

Going deeper into the cave, the tourists will surely be surprised by the stalactite structure uniquely formed resembling the terraced fields full of shining bright rice plants, regionally called "the fairy's field". Besides, there are hundreds of stalactites hanging down softly resembling an attractive curtain. This second chamber is about 200m long, with a sandy ground. The cave sides adorned by the stalactites look like the classic Chinese landscape painting with mountains, rivers, and forest.