Close to the border Bai Tu Long Bay and Lan Ha Bay, an enclosed group of islands create the caves. A see-lake is formed by the imposing islands sheltered from the blows of sea wind and only connected with the sea through a 4 meter wide, 100 meter long, and 3 meter high mouth. The people compared the lake inside with a stadium surrounded by high podium. The traces of fossils of fresh-water snails are found on the cliff, which prove that it was a human habitat in the past and must have been a deep valley then.
Long and short, dark and light tunnels
Just at the base of the islands, the grotto is led to right at the water level by an arched entrance. Behind the natural entrance is a tranquil round lake, surrounded by luxuriant trees with different sized stone walls, weeping fig trees shading inside and many orchids hang their sweet-scented flowers. In the lake, many species abound: shrimp, fish, crab and cuttle-fish and corals. Because the Dark Cave is the long and dark one, visitors need to prepare a torch to be handed. On the contrary, the Light Cave is short, and you can see the other bright side from this side. The beauty of the site is the mingling of a number of factors: the mountain’s size and form, the color of the water and the clouds.
Some Tips To Explore The Dark Cave & Light Cave
- It is no problem to discover the Light Cave, but be careful with the Dark Cave because it can be swallowed by the tide and difficult to pass through.
- The best way to explore the cave is kayaking and swimming.