Situated in the centre of the UNESCO-declared World Heritage area, the Sung Sot or Surprise Grotto is on Bo Hon Island, and is one of the finest and widest grottoes of Ha Long Bay.
Ascending to the grotto, the way is covered by trees and foliage, and consists of great paved stone blocks. Inside, it is partitioned into two chambers; 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.
At the deepest point of the grotto, a “royal garden” appears with a clear pond and a seemingly fascinating landscape of mountains. Many birds and plants (benjamin figs, cycads and centenary banyan trees) live here. On nice days groups of monkeys might arrive in search of fruit.
From the wharf, you climb 50 steep stone stairs to the mouth of the grotto, which lies 25 m above the sea level. Going down some 10 stone stairs, you reach the mouth of a grotto. Sung Sot cave covers some 10,000 m2. There are thousands of stalactites and stalagmites along the 500-meter paved passage. Light posts line the passage and illuminate the amazing scenery. Spotlights of varied colors are placed in such a way to be unobtrusive and add to the enchantment of the grotto.
Up in the 30-meter roof of the grotto, one can figure out small, soft and even concave spots, which look like patterns in the ceiling of a theater. A huge piece of stone stands up to the ceiling by the grotto’s mouth. This evidences one of the typical karst-style grottoes with high scientific values.
At the side of the entrance, the rock seems to form the shape of a horse with a long sword. Legend has it, that after having defeated the An aggressors, Thanh Giong (the Saint Giong) helped the population to chase away evil spirits and demons. After this feat, Saint Giong flew to heaven, leaving a stone horse and sword to continue to keep the demons away.