The world's largest cave is the Son Doong Cave in Vietnam. Located in the Quang Binh province, it was created between 2 and 5 million years ago by river water eroding away the limestone underneath a mountain.

Son Doong Cave, Vietnam

Son Doong cave is more than 200 meters in width, 150 meters height and 6.5 kilometers in length, with caverns big enough to fit an entire city street inside them, twice as large as Deer Cave in Malaysia.

At present, bookings to Son Doong cave are full for 2014, according to Oxalis International Travel Company, which is permitted to pilot the adventure tour to the world biggest cave.

Besides Son Doong Cave, the most breathtaking caves in the world include Phraya Nakon Cave and Morakot Cave in Thailand, Waitomo Glowworm in New Zealand, Crystal Caves of Naica in Mexico, Blue Grotto in Italy, Fingal in Scotland, Lascaux in France, Orda Cave in Russia, Eisriesenwelt in Salzburg, Austria, Reed Flute in China and Crystal Cave in Bermuda.

www.quangbinh.gov.vn