Early one October morning in 2018, a small boat dropped 10 cavers and one scientist into the ocean off the northern coast of Christmas Island. With food, cameras, maps and scientific gear stashed in drybags, the team began a three-hour swim into the maw of the island’s most extensive cave system: Lost Lake.
It was 8:00 am, and they were on a tight deadline.
“It was a race against the tide to get to the back of the cave before the water would hit the roof in the lower chambers,” explains Katrina West, the expedition’s researcher, from Curtin University in Perth.
Snorkels in mouths and wetsuit-clad, West and the cavers – all from the Western Australian Speleological Group (WASG), including trip leader Rob Susac – managed to reach the back of the cave where the chambers sloped upwards. This gifted them a precious few hours to explore the cave system before the tide began to fall again and they had to embark on another three-hour swim back to the boat.
The Lost Lake system was like a descent into another world, with vast chambers full of crystals taller than humans and massive flowstones formed over years as water seeps down walls.
“To get into a place like that was insane,” West says. “It’s just amazing that these big systems can develop for thousands of years in darkness and no one really knows about them.”
But to reach such places was
