ISLE OF PINES, New Caledonia — Human skulls hang from the entrances, and footsteps are said to disappear as if by magic outside New Caledonia's mysterious limestone caves.
Indigenous Kanak tribesmen on the South Pacific islands stay well away from the water-filled caverns where the remains of ancestral warlords have been laid to rest in a world said to be peopled by the age-old spirits of the land.
But for tourists, scuba-divers and what the French call "speleonauts"--deep water-diving speleologists--the caves tucked away in the jungles of the sun-baked French islands provide sport and discovery.
On a narrow dirt track fringed by towering ferns, a group of divers, flippers in hand and tanks belted on backs, move toward a gap in the greenery.
The mouth of a cave opens onto a vast cathedral-like chamber where thick columns of lace-edged stalactites and stalagmites, millions of years old, frame a gateway to an underwater lake.
60 Feet Underground
With a plop, the five wet-suited divers disappear below the still, black waters of this eerily silent world about 60 feet under the ground.
Half an hour later, the explorers from Australia resurface ecstatic from their first cave-dive into one of the few fresh water cave-diving sites in the world.
"Imagine walking around in tunnels and underground cathedrals studded with strange rock formations and then jumping into the air and floating among the stalactites and stalagmites," said diver Brad Henderson.
"But you wouldn't want to be claustrophobic down there," said Laurie Hall.
Guide Albert Thoma, a 53-year-old Swiss diving buff, takes only the most experienced divers into the underworld apparently formed by a geological accident.
5 at a Time
Because the silt haze can reduce visibility to arm's length, Thoma takes at most five divers down at a time. He then waits four to 10 days for the silt to settle before taking a new group through the 250-yard labyrinth of tunnels.
"But aside from safety reasons I also reject inexperienced divers who might damage the site," he said.
Thoma left a job as an interior decorator in the 1960s and came to the Pacific in search of a place where he could set up a deep-sea diving business.
Drawn to the Isle of Pines, 40 miles southeast of the New Caledonian mainland, Thoma says he would not budge from the tiny island for all the money in the world.
Ringed by its own coral reef and a mirror-like lagoon full of fish and plant life, the volcanic island was charted by Captain Cook in 1774 and visited by Protestant and Catholic missionaries and sandalwood traders.
In 1872, Paris turned it into a penal settlement, deporting nearly 3,000 insurgents of the radical Paris Commune to stone jails.
18 Ships a Year
Today the 1,400-strong population welcome 18 tourist ships a year. Up to 1,500 tourists at a time have a native lunch and quick plunge before sailing elsewhere.
On New Caledonia's Loyalty Islands, east of the mainland, speleologists Christian Thomas and Jean-Francois Cherrier have pinpointed and charted a new series of water-filled caves, one of which holds what they say is the world's largest known underground lake.
Like the Isle of Pines grotto, the caves they have discovered and explored are studded with stalactites and stalagmites as well as the apparent remains of a large underground forest.
Fewer than 1,000 divers have ventured into the New Caledonia caves, Thomas said in a recent interview. "There are few speleonauts because one finds oneself in extremely aggressive and tense situations so easily."