The rocky passage is 150metres long and measures a towering 200metres in height - seven times as high as York Cathedral
'It is a truly amazing sized cave and one of the most significant discoveries by a British caving team,' said Adam Spillane, a member of the 13-man expedition team.
The cave was originally discovered in 1991 by a Vietnamese Jungle man called Ho Khanh.
Local people had known of the cave but were too scared to delve inside because 'it emitted a frightful wind and noise which was due to a large underground river‘.
But assisted by representatives of Hanoi University of Science, the joint British-Vietnamese Caving Expedition 2009 spent five days exploring the cave in mid-April.
The team spent six hours trekking through the jungle to reached the cave. Climbing down into a large chamber, they had to negotiate two underground rivers before reaching the main passage of the Hang Son Doong.
The cave is 6.5km long at present but the end of the main passage still continues with a calcite wall of over 45m high halting team’s progress.
The team found an underground river running through the first 2.5 kilometers of the limestone cavern, as well as giant stalagmites more than 70 meters high.
At least 80-by-80 meters in most places, the Son Doong cave beats out the previous world-record holder, Deer Cave in the Malaysian section of the island of Borneo. Deer Cave is no less 91-by-91 meters, but it's only about 1.6 kilometers long.
For a couple of kilometers it is more than 140 meters wide and 140 meters high
Reason to not detected
Son Doong had somehow escaped detection during previous British caving expeditions to the region, which is rich in limestone grottos.
The terrain in that area of Vietnam is very difficult,
The cave is very far out of the way. It's totally covered in jungle, and you can't see anything on Google Earth.
You've got to be very close to the cave to find it,
Certainly, on previous expeditions, people have passed within a few hundred meters of the entrance without finding it.
The team was told that local people had known of the cave but were too scared to delve inside.
It has a very loud draft and you can hear the river from the cave entrance, so it is very noisy and intimidating.
END of Prensentation