The Nguom Ngao is one of the largest cave located inside a mountain among the range of limestone mountain in Gun hamlet, Dam Thuy commune, Trung Khanh district.
The cave was formed due to weathered process of limestone mountains over a long time. Stepping in the cavern, we seem to see a miraculous world. From high stone cliffs, hanging wonderful sparkling seven-colored stalactites. The nature busy with its work over a long time to create attractive stone statues of which some look like human bodies, some look like forest trees, animals of fairy tales, or a fairy combing her hair, or a good divine, or a huge lotus bulb. Stalactites seem to grow from the soil, or hang down, vertical or horizontal with small and big figures piled and fixed in a hustle indulging visitors.
Wonderful beauty of Nguom Ngao spreads the cavern. According to figures given by the British Royal Investigator Group in 1995, Nguom Ngao is 2,144m long including 3 main entrances namely Nguom Ngao, Nguom Lom and Ban Thuon.