Maybe it's our caveman past, but people love holes in the ground. Whether it's digging in the sand at the beach, peering into an apocalyptic sinkhole, or perhaps even dabbling in spelunking, we are fascinated by the subterranean.

It's surprising then that it took so long for extreme caving to round into form as a serious pursuit of exploring the truly great natural spaces deep in the planet. Though the roots of extreme caving go back to the middle of the 20th century, it wasn't until several years into the 21st that the deepest known "supercave" was explored beyond 2,000 meters (6,561 feet) below the surface.

The discovery happened in 2004 in a supercave called Krubera, in the war-torn Republic of Georgia. It was one of the greatest exploratory accomplishments of this or any century, on par with climbing Mt. Everest, diving Challenger Deep, or landing on the moon. And yet, the story remains largely out of the limelight.

It's easy to see why. Caving is dark, dirty, unnerving work. When not squeezed into rib-cracking passageways or rappelling down 500-foot shafts, cavers are worrying about hypothermia, trying not to be soaked by roaring underground waterfalls, and staving off the psychological effects of prolonged exposure to absolute darkness.

In his new book, Blind Descent, author James Tabor takes us inside the incredible world of extreme caving to meet the men and women who choose to toil in it, and the unbelievable natural challenges they faced in racing to the bottom of the world.

Much of the book follows the brash, inventive American genius caver Bill Stone, who pushes the limits of technology and human endurance seeking the bottom of the Cheve cave system in Mexico. We are introduced to a man of mind-boggling ambition, a man who puts his life on the line (and arguably is responsible for the deaths of more than one team member) to find the planet's deepest hole.

All along, Tabor sprinkles in details that bring the haunting underground world home to the average surface-walking reader. Depths of 500, 1,000 and more feet are tossed around a lot, and it's easy to get lost in a sea of subterranean figures. He translates for us, saying that a rock dropped takes six seconds to get to the bottom of some of the bigger shafts. Imagine dropping a stone down a hole, then count it out in your head. Yeah, that's a big hole.

Then there are the hazards — suffocating, getting lost, getting crushed, drowning, "air belaying," infections from bat guano, even a special psychological hell called The Rapture — these make up a very incomplete list of the things that can kill you in a cave.

Ultimately (spoiler alert) it's the Ukrainian caver Alexander Klimchouk and his team that push Krubera to its record-breaking depths.

But as with any good story, it's all about the journey, and Tabor doesn't disappoint. Right from the get-go describing the death of a novice caver, it's a page-turner, and the book flies by, sucking us down, down into to some of the most alien landscapes on the planet and forcing us to enjoy the descent.