Deep within the heart of Halong Bay, within the picturesque Bo Hon Archipelago, lies Trinh Nu Cave, known to many as the “Virgin Cave”. Just 3 km to the southeast of Sung Sot Cave, a visit to the Trinh Nu Cave blends the spellbinding natural beauty of Halong Bay with the quaint folklore imprint of Vietnamese heritage.

Halong Bay's largest and most famous cave, Sung Sot Cave consists of two major chambers. The first, comparable to a theatre hall, features numerous stalactites hanging from the ceiling. From here a narrow passageway leads to the massive second chamber, where a flow of natural light brightens the surfaces of a space roomy enough to hold thousands of people. Sung Sot Cave's 10,000 square meters of space hold thousands of stalactites and stalagmites, and are threaded by a 500-meter paved passageway.

Me Cung Cave, located on Lom Bo Island some 2 kilometres southwest of Titop Island, has numerous chambers linked by small passageways often just large enough for one person to pass through at a time. Me Cung Cave is notable as the site of archaeological evidence of prehistoric life in this area. Initial scientific explorations of the cave revealed piles of freshwater seashells along with fossilized animal remains. Experts believe the cave was inhabited some 7,000 to 10,000 years ago by a Stone Age culture using the bay as a food source.

Considered the most beautiful cave in Halong Bay, Thien Cung Cave is located only a few km from Halong City, the embarkation point of most Halong Bay cruises. The cave's vast interior is some 3,000 square meters, including several levels and impressively high ceilings. The stalactites and stalagmites in Thien Cung Cave come in many forms, and visitors enjoy learning the local stories about them, including the legend of the Dragon Prince falling in love the Lady of the Clouds.