Covering an area of nearly 1,000 m2, the cave is spectacular for its sheer size. It is separated into two chambers by a tall rustic stone pillar. The cave door, after thousand years of direct contact with sea water, has been covered with a layer of emerald green moss, giving it a primitive charm. The system of stalactites inside Tien Ong Cave is nothing short of stunning compared to those inside the finest caves in Ha Long Bay, such as Sung Sot Grotto or Thien Cung Cave. They can take any forms and shapes, from peacock, crocodile or a mighty man. Recently they have been ornamented with well-manicured lights to look all the more magnificent. The grotto can be likened to a hauntingly beautiful museum built by Planet Earth.
Besides its natural beauty, Tien Ong Cave also draws attention from archaeological experts for containing stone artifact assemblages from Hoa Binh Culture that dated to 10000-2000 BCE. If you’re lucky to go with a knowledgeable and experienced guide, your trip will be even more eye-opening with fantastic history lessons of cave exploration. Tien Ong Cave was officially opened for tourism in 2010, satisfying both Ha Long Bay enthusiasts and archaeology buffs.