The Son Doong (translated as "river mountain") cave in Vietnam is 9 kilometres long, 200 metres wide and 150 metres high - and barely anyone knew it existed until four years ago. Although a local had found the entrance to the cave back in 1991, it wasn't until 2009 that a group of British explorers actually discovered the staggering size of the place. It has subsequently been confirmed to be the world's largest cave by the British Cave Research Association.

Son Doong was created 2-5 million years ago by river erosion, and in some spots weak limestone has collapsed to create massive skylights in the ceiling.

Now, one tour company has finally decided to bring members of the public through the giagantic natural structure. The week long expedition includes three days and nights within the cave. Tourists (up to 8 per trip) will be accompanied by over a dozen porters, and traverse jungles, cliffs and waterways within the cave.

Unfortunately, this does not come cheap, with tour company Oxalis currently charging over €2,250 for the privilege. Still, for the adventurous traveller, it promises to be an extraordinary trip through a completely unique structure.

Check out the video below for a glimpse at some of the things the tourists will experience on their trip:

(Photo: Matos 15)