Big Pacific

(sonar beeps) -

Narrator

Sabah in Malaysia. Some of the world's richest rain forests run to the water line, where a new natural wonder begins, a coral reef system of immeasurable richness that hides a mysterious graveyard, through a dark cleft into a maze of drowned caves, a perilous journey for even experienced divers, 60 feet down and then more than 200 feet into the heart of the island, the tomb of the lost turtles. One turtle might wander in and never wander out but dozens? After visiting in 1998, undersea explorer Jacques Cousteau likened it to a graveyard for African elephants, a place where they go to die. But Africa's elephant graveyards are a myth and sea turtles don't gather to die. This is the only one we know of. Other clues only cloud the mystery. Dozens of shells lay in the sand. They're all that's left of still-born offspring but females lay their eggs on beaches not in caves. The water is pitch black so we might get lost in here but turtles? They can hold their breath up to seven hours and they're one of the best navigators in the sea. How do they manage to cross thousands of miles of the big Pacific, yet not find their way out of here? The crypt remains ever cryptic.