World's largest cave in Veitnam

This cave was found in 1991 due to a natural disaster. It is known as Hang Son Doong cave. This cave is not less than any wonder of the world. The height of this cave is 660 feet whereas the width is almost 490 feets. When scientists started researching about this cave, they came to know that sunlight and air enters this cave from different sides due to which alot of plants and vegetables were found there and the height of the trees in the cave is almost 100 feets. Even different type of animals and birds were living in this cave. In adition to this, a lake was found and the water of that lake goes into any other cave that is still undiscovered. Tourists from any part of the world need to take permission from veitnam government to visit this place because of security reasons, as in rainy season, it is not allowed to go into this cave because of tourist's security