The largest cave in the world is located in Vietnam.
This cave is 200m high and 150m wide.The largest cave is 5 km long.
It was discovered in 1991.It is relatively young, some research says it is 3 million years old and other research says it is 3.5 million years old.
This cave is so big that it has its own climate,river and jungle in it.
Pictures are from http://www.neatorama.com/spotlight/2010/12/20/the-worlds-biggest-cave
http://www.businessinsider.com/inside-worlds-largest-cave-vietnam-hang-son-doong-2015-3
