Ha Long bay was naturally formed by geological movement million years ago. As a result, , many caves and grottos in this area were formed with many shapes, different characteristics and own legend.
The first one worth mentioning is Thien Cung Grotto (Heaven Grotto) which is about 8 kilometers away from Halong Bay and 4 kilometers from the wharf called Van Canh. Thien Cung grotto is among one of the most beautiful grottoes in Halong, which has thousands of stalactites, stalagmites shaping a marvelously natural palace. In the centre of grotto there are four large pillars supporting the “roof of heaven”. Many strange images were carved on the stone from the base to the top, including birds, fish, flowers and even scenes of human life. On the north wall of the grotto, there is a scene of fairies dancing and singing to celebrate the wedding. When standing inside this place, tourists can hear the sound like a drum beating which actually is the noise of the wind blowing through stone. At the last part of the grotto, a natural ravine murmurs throughout the year. There are three small ponds containing crystal water inside. Thien Cung grotto (Heaven cave) is definitely a unique, meticulous, interesting fine-art museum created by nature that beyond any ability and intellect of man.
Next is Surprising Cave (Amazing Cave) which is one of the largest and beautiful caves in Halong bay with thousands of stalactites and usually will be arraged in the fist day of Halong Bay 2 days or 3 days tours. Situated in the centre of the UNESCO World Heritage area, Sung Sot or “Surprise Cave” is on Bo Hon Island, and is one of the most spectacular and largest caves of Ha Long Bay. The mouth of the cave is reached by ascending about a hundred stone steps. One is surrounded by trees and foliage on the journey up as the shimmering bay below offers an ever more panoramic view to admire. The cave includes two chambers and a “royal garden” with a clear pond and a fascinating landscape of small mountains. Walking through the cave ones imagination can run wild conjuring up all kinds of fantastic creatures and fanciful creations.
Another beautiful structure in Halong bay is Dau Go cave (Driftwood cave) which was named after a legend told that Tran Hung Dao general used the cave as a warehouse to keep pointed piles of ironwood, a kind of weapon that helped our army defeated Nguyen-Mong army in Bach Dang river. Entering the cave, tourists will discover a magnificent world of stalactites and stalagmites with various sizes and shapes which are the results of karst process in a long period. They seem like lively statues, reliefs about nature and people on Halong Bay. These masterpieces of the Creator will certainly be very impressive to visitors coming to Halong, especially when accommodated with mysterious light.
Different from Dau Go cave, Trinh Nu cave (Virgin Cave) is famous for the legend about a sad love story. For fishermen, the Virgin Grotto is their house, but for young lovers, it is considered as the symbol of truly love, and is the romantic place for taking oath of love. Nowadays, when entering Trinh Nu cave, one finds in the middle of the grotto a stone statue of a lying-girl with her long hair hanging down who is looking to the sea in a vain hope. Situated opposite to Trinh Nu cave, Trong (or Male) Grotto has a stone statue of a boy who turns his face to Trinh Nu cave. One still hears his vain scream in tune with the wind blowing into the cliff somewhere. Such a sad and painful love story but the beauty inside the cave is amazing and you should not pass it when in Halong bay.