By Katie Mettler

The Washington Post

The sign at the mouth is black and white, its macabre message clear.

“STOP. PREVENT YOUR DEATH!” it warns. “THERE’S NOTHING IN THIS CAVE WORTH DYING FOR!”

Beside these words looms an image of the grim reaper.

The sign guards one of Florida’s most treacherous underwater caves, Eagle’s Nest Sinkhole near mermaid-famous Weeki Wachee, a network of narrow nooks and lightless pockets that cradle rubble and nurture a home for peculiar, translucent marine life. The pathways plunge 300 feet in the deepest spots and stretch for a mile along the state’s porous limestone crust.

“It’s like a Venus fly trap,” Sylvester Muller, vice-chairman of the National Speleological Society’s Cave Diving section told the Sun-Sentinel. “You get in there and there is so much to see you get distracted, and it gets deep quickly.”

Among the adventurers brave enough to explore these underwater caverns, Eagle’s Nest is considered one of the planet’s most dangerous dives for its extreme depths and mazelike architecture. It has been called the “Mount Everest” of cave dives.

And just like Everest, this natural wonder has killed those attempting to witness its beauty.

Before Sunday, when three friends ventured into Eagle’s Nest’s depths as part of a three-day dive, the cave had claimed at least eight lives, according to the Tampa Bay Times, including a father, son duo on Christmas Day.

Two of the men on Sunday, Patrick Peacock and Chris Rittenmeyer from Fort Lauderdale, were experienced divers who had explored Eagle’s Nest before, authorities said. The third friend – Justin Blakely – had not.

At about 2 p.m. Sunday, the men, with their scuba gear, entered the water that masks the entrance to Eagle’s Nest, a swampy looking pond buried deep in the Chassahowitzka Wildlife Management Area located in Hernando County, a coastal region in west-central Florida.

Peacock and Rittenmeyer, the more experienced divers, explored the dark caves while Blakely remained close to the surface. The trio planned to reconvene at a predetermined location at 3 p.m.

Blakely arrived on time. His friends did not.

The lone diver returned 30 minutes later, but Peacock and Rittenmeyer were still gone.

A half-hour later, he tried again. Nothing.

By 6 p.m., Blakely called police.

Rescue divers combed the cave Sunday evening, searching for the missing friends, but they could not be located in its labyrinths. It wasn’t until Monday morning that a fresh crew of rescuers located Peacock and Rittenmeyer. Their bodies, trapped at a depth of 260 feet, were found not far from each other, according to the Hernando County Sheriff’s Office, in a “very dangerous and complex area of the cave system.”

The deaths of these divers, considered experts by Blakely and others, has renewed a decades-old debate over whether Eagle’s Nest, proven time and time again to be lethal, should be closed off to the public – for good.

The state barred entrance to the sinkhole in 1999, reported the Tampa Bay Times, and it was later reopened in 2003 amid pressure from the National Association for Cave Divers and the National Speleological Society Cave Diving Section. The Florida Fish and Wildlife Conservation Commission spent $12,000 to build a boardwalk, pier and stairway on the lip of the pond, making it safer for divers to access Eagle’s Nest, according to the Times.

One of the most prominent access advocates at the time was diving instructor Larry Green.

“There’s a mystique about it, because people all around the world know about this dive site, but very few people have actually dove it,” Green told the Times in 2003.

Critics argue that despite numerous signs warning of the cave’s grave dangers, the network is too treacherous to keep open to the public. There is no way to prevent divers with inadequate experience – like the father, son duo killed on Christmas – from venturing into the depths. And when there is a tragedy, rescuers are forced to endanger their own lives to search for the missing.

“This is so tragic and completely preventable,” wrote one woman on the Hernando Sheriff’s Office Facebook page.

“This dive spot should be closed for good,” wrote another.

On Monday, the rescue divers were private volunteers because the expertise necessary to retrieve the men exceeded the authorities’ abilities. They swam the men back through the dark maze, reported Fox 13, then later returned for the men’s equipment.

At this point, its unclear what happened to Peacock and Rittenmeyer underwater, or why the two men were unable to resurface.

“They may have lost their line, they may have lost visibility, they may have been restrictive, there may have been gear issues,” Matt Vinzant, a local diver with more than 50 dives at Eagle’s Nest, told Fox 13. “We don’t know at this point but more than likely it was a series of issues.”

The divers’ bodies were taken to the Medical Examiner’s office to determine cause of death.

One common cause of death among divers who tackle extreme depths is a condition called nitrogen narcosis.

Nicknamed “Rapture of the Deep” or “Martini’s Law,” this altered state of mind is caused when the amount of nitrogen in the mixture of gases breathed in underwater is too high. Divers call it Martini’s Law because, like drinking the cocktail on an empty stomach, the unbalanced levels can feel a lot like inebriation. The deeper a diver goes, the more drunk they can feel.

And that altered state can prevent a diver from recognizing the trouble they’re in.

“You have a lack of judgment and lose some of your inhibitions,” Chuck Walls, a local diving instructor, told ABC Action News. “Some people may even freeze up and do what we call ‘white out.’”

Perhaps the most tragic deaths at Eagle’s Nest occurred on Christmas Day in 2013, reported the Times, when Darrin Spivey and his 15-year-old son, Dillon Sanchez, trekked to the cave to test out their Christmas gifts – brand new air tanks. Spivey was a certified diver but his son was not.

A local expert told the Times it appeared the father and son had descended through the narrow tunnel entrance into the cave and were exploring the gymnasium-size room there, known as The Ballroom. They dove as deep as 233 feet, their air gauges revealed, and had apparently run out of air.

The teen boy likely ran out first, the Times reported, and his father let him breathe from an extra long breathing hose attached to his tank.

But the duo couldn’t reach their spare tank in time.

The boy was found floating near them, at a depth of 67 feet. His father was recovered on the Ballroom floor, at a depth of 127 feet, according to the Times report.

Though the father and son were not properly trained to dive such a complicated and dangerous cave, the Eagle’s Nest has claimed the lives of even the most advanced divers.

On Facebook, a man named Gary Shatzkin who identified himself as a friend of the Fort Lauderdale divers who died Sunday, said the men were well-equipped. Peacock was a diver instructor.

“They both had years of training and have dove in cave systems throughout not only Florida, but Mexico and South America,” Shatzkin wrote on Facebook. “We are in shock here as you would be hard pressed to find two more competent, by the book, experienced cave divers.”