Journey to the centre of the earth
Once feared by explorers as a killer cave where all but the most daring feared to tread these pictures show how humans have triumphed over the underworld.
At 3,680-feet deep (about two-thirds of a mile) six people, including one-female Briton have died while exploring the Gouffre Berger limestone cave in south eastern France.
It was the first cave to be explored over 1,000 metres under the surface of the Earth and was named after the man who discovered it – Frenchman Joseph Berger.
It's possible to get to the bottom in a day but I camped for three days so I could spend time on my pictures.'
Cavers, many of whom were British, used ropes to rappel down vertical shafts and swam across hauntingly beautiful underground lakes.
The adventurers were dwarfed by mighty formations as they used lanterns to navigate the huge caverns.
Into the abyss: The Gouffre Berger limestone cave in south eastern France was the first over 1,000 metres deep to be explored
'There are sheer drops to descend,' said Robbie. 'As well as passages flooded with water. Once the bottom is reached there's a real sense of being someone very deep underground.
'There are the initials of the original explorers in the last flooded cavern. That's the end for dry cavers – those who don't cave dive underwater.
'After that if you want to go further you have to pull on diving gear and explore the totally flooded tunnels.'
First discovered in 1953 it was the deepest known cave at the time – and has a rich history of British achievement with the world record for the deepest cave dive going to British diver Peter Watkinson and his team in 1967.
Watkinson and other team members received international acclaim for reaching the deepest point possible on foot and then completing a perilous 130-feet underwater dive.
Because of Gouffre Berger's limestone walls water can penetrate the cave is liable to flooding after heavy rainfall, which caused five of the deaths, including Briton Nicole Dollimore from Oxford in 1996.