World's Biggest Cave : Found in Vietnam
A local farmer had found the mouth of Son Doong cave several years ago in the dense jungles of Vietnam's Phong Nha-Ke Bang National Park. He led the British expedition team to the cavern in April. The team was told that local people had known of the cave for some time but were too scared to delve inside.
The joint British-Vietnamese team that explored the cave in April found an underground river running through the first 1.6 miles (2.5 kilometers) of the limestone cavern, as well as giant stalagmites more than 230 feet (70 meters) high.
The cave measures at least 262-by-262 feet (80-by-80 meters) in most places and is at least 2.8 miles (4.5 kilometers) long.
"For a couple of kilometers it is more than 140 meters [460 feet] wide and 140 meters [460 feet] high," said Adam Spillane, a member of the British Cave Research Association expedition that explored the massive cavern.