A spectacular limestone cave on Dau Go Island in the western part of the heritage zone, often visited on the same itinerary as the nearby Dau Go Cave. The chambers extend roughly 130 metres into the island and rise up to 20 metres high, packed with elaborate stalactite and stalagmite formations that have been given mythological names by Vietnamese guides.
The cave is reached by a flight of stone steps from the boat landing. The interior is paved and well lit, and the tour takes about 30–40 minutes. The lighting is theatrical — coloured floodlights play across formations meant to represent dragons, princesses, and wedding processions. Some find it kitschy; others find it adds to the atmosphere. Less visited than Sung Sot Cave further east, Thien Cung is a good alternative for cruise itineraries that want to avoid the day-trip crush.