Son Doong cave in Quang Binh, Vietnam is the largest in the world, has opened to tourists.
Along the algae-covered road maze, two adventurers Deb and Howard Limbert go through natural sculptures formed from calcium-rich water flowing in the cave. Photo: National Geographic.
Tour price is 3000 USD/ person.
Son Doong cave 9km. Before discovery of Son Doong cave, Deer Cave in Borneo cave record holder for the world's largest 5 km long, 200 meters high and 150 meters wide.
Son Doong cave is located near the border of Vietnam - Laos, in the national park Phong Nha - Ke Bang.
Surrounding forest and remote locations Son Doong help not detected in a long time.
The world's biggest cave