Son Doong cave is the largest cave in the world in Vietnam. It is 5.5 miles long, a forest and a river, and a 40-story skyscraper could fit inside its walls.
But nobody knew that about six years ago.
Recently discovered cave, the largest in the world competing for the longest title of the other caves have been introduced as the (Brownsville's Mammoth Cave in Kentucky, about 400 miles along corridors nabs title ) and intensive (Krubera cave in the state of Georgia).
A local man discovered the entrance to the cave in 1991, but in 2009 the first British cavers were to find out. Oxalis trial tours to the cave tour company two years ago after running.
Son Doong people who are lucky so far, as photographer John spies, have been recorded with some amazing photos have emerged.