Filmmaker Dick Colthurst went to Mount Everest hoping to learn why people risk their lives trying to reach the world's tallest summit. After spending 48 days in that unforgiving landscape and slogging through hundreds of hours of footage, he has to admit that he failed.

"While I admire what they do and how they do it, and the sheer mental and physical strength that it takes to do it, I'm honestly no nearer to understanding why they do it," said Colthurst, an executive producer for London-based Tigress Productions.

But Colthurst and his crew did succeed in capturing in vivid and often disturbing detail the hell climbers put themselves through to be able to say they've been to "the roof of the world."

"Everest: Beyond the Limit," which begins its six-week run tomorrow on Discovery Channel, chronicles the journey of eight men during the 2006 spring climbing season — the second-deadliest on the Himalayan peak that rises over 29,000 feet.

There's the asthmatic school teacher from Denmark who is trying to reach the top without supplemental oxygen; the former Hell's Angel whose near-fatal motorcycle wreck left him with two metal plates in his head, one in his left knee, 10 screws in his left foot and a steel cage holding his lower back together; a Los Angeles firefighter who had sold his Harley-Davidson and mortgaged his house to finance a failed summit attempt the year before; and a 62-year-old Frenchman who just two months earlier had a cancerous kidney removed through his belly so the incision wouldn't impede his ability to carry a backpack.

The series' "star" is New Zealand mountaineer Mark Inglis. Inglis lost both legs just below the knee to frostbite 24 years ago and is seeking, on specially designed carbon legs with spiked feet, to become the first double amputee to climb Everest.

Leading the expedition is New Zealander Russell Brice, who has put more people on Everest's summit than any other commercial guide and had never suffered a casualty in 13 trips to the mountain.

The series skips the niceties of Katmandu and the picturesque Buddhist monasteries that cling to the valley beside Everest, and takes you straight to base camp — at 17,060 feet already higher than any peak in the Rockies.

Bouncy, topsy-turvy footage shot by cameras mounted on sherpas' helmets gives the viewer the queasy, almost stomach-churning illusion of climbing. The camera is unflinching.

Watching Inglis inch upward on his spindly black prosthetics, blood from his raw-rubbed stumps staining the pristine snow, it's hard to know whether to feel inspired by his guts or infuriated at his foolhardiness.

"It's a view to die for," one climber says without a hint of irony.

Each episode ends in a genuine cliffhanger. Will the rebellious biker heed Brice's order to turn around before his oxygen runs out? Caught in a traffic jam behind a line of incompetent amateurs, will the team physician lose his fingers to frostbite?

There are dramatic rescues. And there is death.

The Tigress crew was there when members of Brice's expedition discovered British climber David Sharp, who froze to death as dozens passed on their way to the summit. The incident made international headlines and brought widespread condemnation down on Brice's head for not mounting a rescue.