BBC2 Saturday 11 July [today] 9.00am to 10.00am.  Steve Backshaft?s Extreme Mountain Challenge.  Worth looking out for on I-Player.
Tepuis, rocky tabletop mountains isolated by hundreds of metres of steep cliffs, form a unique habitat on their tops and inside their maze of caves. Untouched for millions of years, they host a secret world that has evolved in parallel with its surroundings.
Now, the secrets of the ancient tepui are slowly being revealed, thanks to expeditions led by speleologist Steve Backshaft
Earlier this month, his team finished an arduous, 40-day expedition to some of the world?s last unexplored caves inside inaccessible tepuis. His team explored Imawar? Yeuta in Venezuela, which has at least 22 kilometres of tunnels, the largest known cave system of its kind.

My neighbour mentioned this earlier today. As a non-caver, he thought it was very interesting. Will take a look on the iplayer

rhychydwr1 said:

Steve Backshaft?s

Click to expand...

This was repeated last night, and can be seen again < here >. Worth a watch if you haven't seen it, particularly for the bizarre sandstone caves. You do have to put up with Steve Backshall going "WOAH, AWESOME' or similar every few minutes, though to be fair, the scenery is awesome.

JoshW said:

Click to expand...

A Freudian slip

You can find some articles in old Descent magazines. Arthur Conan Doyle got it right when he had his explorers escaping the lost world (thought to be Roraima) through a network of caves.