Son Doong, Vietnam
Consider yourself lucky if you ever get to visit Son Doong cave in Vietnam. This cave was first discovered in 1991 by a local, but it remained unknown to the public until the British Caving Association ‘rediscovered’ it in 2009.
Since then, the cave has become well-known as the largest cave in the world as well as being home to the ‘Hand of Dog’ stalagmite, possibly the largest stalagmite in the world.
The cave is only partially open to tourism, and most of the cave is still unexplored. About 200 tourists are allowed access each year, so if you ever have the opportunity to go to this wonder, you should definitely seize it!