Vietnam destination- Son Doong cave, which was discovered in 2009 by the British Caving Association, is estimated to be the largest in the world with a width of 150m, a height of more than 200m and length of 5km.
Transportation: From Hanoi, you can take a train to Quang Binh, then take a car to the Ho Chi Minh trail and to the cave.
Notices: At present, few visitors are able to visit Son Doong cave on tours costing 3000$. With this trip, you should be in good health because you will have to walk and climb up to the cave in the forest.