The Son Doong Cave in Vietnam is the largest in the world and has its own underground river and jungle.
It was discovered in 1991 by a farmer. There are no signs that anyone has ever lived in this cave or knew about it before this date.
Son Doong means “Mountain River Cave” in Vietnamese. The cave not only contains a river, it also has its own jungle and the largest stalagmites in the world (up to 70m tall).
In 2013 the first tourists entered the cave. A guided tour of the cave costs $3,000 per person.
Photos from: LaVozDelMuro.net