Inside World's Biggest Cave

Into the depths of the earth: Cave network in the heart of Vietnamese jungle is so large its end is yet to be found

  

These are the breathtaking images which capture the hidden depths of the world's biggest cave passage, which still has left cavers still searching for its end.

Hidden in the depths of the Vietnamese jungle lies The Hang Son Doong, part of a network of over 150 caves.

Discovered by British cavers in 2009, the cave passage in Phong Nha-Ke Bang National Park was originally thought to be a modest 150 metres long and 200 feet high.

Intrepid journey: A caver stands in front of a huge rock formation as the light shines beneath a skylight in Hang Son Doong

But these remarkable images - taken during two further expeditions of the caves - show the previously undiscovered depths of the magnificent cave passage, now the largest in the world.

At a mammoth 2.5 miles long, 330ft wide and almost 800ft high, Hang Son Doong also known as Mountain River Cave, is as high as 25 double decker buses.