In early May, Jungle Boss Tours, an adventure travel company that exclusively runs cave exploration tours in the world-renowned cave systems of central Vietnam's Quang Binh Province, announced the discovery of a mysterious lake located in a sub-branch of Thung Cave of of Thoong Valley.
The lake is located around one kilometer from the entrance of the cave, in one of the most pristine caverns in the area. It is situated deep within a strictly protected zone of the national park.
Le Luu Dung, director of the company, said that the expedition team accidentally found the lake during a regular inspection of cave safety systems while monitoring underground river water levels inside the cave.
The lake's surface is about 15 meters higher than the main underground river branch inside the cave, making it look to its discoverers like it was "floating" on the cave wall.
In the photo is a member of the expedition team swims in the lake.
About a week after discovering the lake, the expedition team returned and discovered the lake's water level had dropped 2 meters.
Dung said the lake water level has now recovered, but the cause of the receding water had not yet been determined.
"In June, the expedition team will survey this lake closely," Dung said.
Tiny drops of water ripple the surface of the lake.
Dung said the discovery of the lake would bring new experiences to visitors of Quang Binh, known as Vietnam’s "cave kingdom."
Every year, new discoveries are made in the caves and ecosystems of the Quang Binh’s vast underground and mountain network.
The newly-discovered lake reflects a transparent emerald, or “greenish” color, and has been tentatively named Lo Lung (floating) lake due to its uniquely subtle and disarming appearance and location.
