Sung Sot cave is the most famous cave in Halong Bay which is in the centre of the UNESCO World Heritage area. Sung Sot cave means Surprised Cave or Amazing Cave is on Bo Hon Island and is one of the most spectacular and largest grottoes of Ha Long Bay. The mouth of the grotto is reached by ascending about a hundred stone steps.
Inside, it is partitioned into two chambers. Each chamber has its own beauty which surprises tourists. The first one being similar to a wide theatre hall. Many stalactites hang from the high ceiling, with numerous possible forms and shapes.
A narrow passage leads to the second rooms, where a flow of light meets visitors. The chamber is so immense it could contain thousands of people at one time.
The mouth of Sung Sot Cave is about 25 meters above the sea level. There is a stone in the shape of a horse and a long sword next to the entrance. The ancient legend has told that, after defeating the An Enemy, Thanh Giong flied to Heaven, leaving his sword and horse to reassure local people and dislodge demons. Currently, inside the cave, there are many natural images as the marks of that fierce battle. The trail of his horse became many little lakes and smashed rocks. Sung Sot Cave is typical for karst caves on Halong Bay and has high scientific value in the field of geology.