Human beings were not designed to survive in thin air. Those who stay up too high, too long, will eventually be overcome by the altitude. This is the reason climbers refer to all peaks above 26,000 feet as “the Death Zone.” Mount Everest, at 29,028 feet, is particularly lethal. So when Sandy Hill Pittman reached its fabled summit at roughly 2:30 P.M. on May 10, she wasted no time celebrating, even though it was an achievement she had been working toward for a lifetime.

Pittman, 41, had more at stake than the other climbers who had plunked down around $65,000 for the chance to stand at the world’s apex. Years earlier, bored with life as the socialite wife of MTV creator Bob Pittman (estimated worth, more than $40 million), she had transformed a girlhood enthusiasm for mountaineering and adventuring into a high-profile outlet for her energy and ambition. What had begun as a hobby—trekking in the Himalayas, horseback riding across Kenya, and kayaking in the Arctic Circle—evolved into a passion, a purpose, an identity. Long before she left New York for Nepal on March 21, Pittman had succeeded in fashioning a romantic role for herself as a daring adventuress, a sort of modern-day Amelia Earhart. Sporting La Perla lingerie under her Gore-Tex, she had, in her own words, traded “the escalator at Bergdorf’s” for more exotic terrain. “She’s very inspiring in that she finds a way to live life to its limits,“ says her pal Nina Griscom. Not everyone agrees. “She’s a show-off,” says one friend with a shrug. “When she went kayaking in the East River, she would call up everyone she knew and tell them she was passing. Then she’d get written up in the columns, which is exactly what she wanted. She is a beautiful California girl, but she has a lot of chutzpah.”

Everest was the last peak in Pittman’s grand plan to become the third woman in history to scale the Top Seven, the highest mountains on each continent. The experience would provide an operatic finale to her book-in-progress, already titled Summits of My Soul, and bring her one step closer to realizing her dream of becoming a sportswoman with media tie-ins, the Martha Stewart of mountaineering. A tireless promoter, Pittman tackled the publicity with the same zeal she applied to her demanding training regimen, which included running up the 26 flights to her Central Park West apartment eight times daily. (That’s 208 flights.) Before the trip, she modeled climbing gear for Vogue and made arrangements with NBC for her electronic diary to be transmitted from Everest (via satellite phone) and posted on the World Wide Web. Her farewell party at Nell’s, thrown by society columnist Billy Norwich, was attended by admirers including André Balazs, owner of the Château Marmont hotel, Bianca Jagger, and Calvin Klein. Pittman arrived in full climbing regalia, including crampons and ice ax. Others were treated to a glimpse of Sandy in a snowsuit when the determined mountaineer was featured on postcards with her Web address and a picture of herself hanging jauntily off a cliff. (“All of the excitement; none of the risks,” they promised. “Tie on-line with Sandy Hill Pittman.”)

She could not have put more pressure on herself to succeed on this, her third Everest attempt. Her obsession had cost her hundreds of thousands of dollars and ultimately her 16-year marriage. In October, her husband moved out and is now involved with Veronique Choa, estranged wife of David Breashears, a climber with whom Sandy Pittman had attempted to scale the Kangshung Face of Everest in 1994. For several months, Pittman agonized over her marriage and whether to leave her 12-year-old son, Bo, for the two-and-a-half-month Everest trip in the midst of a divorce. At the last minute, however, she leapt at the opportunity to join an expedition with an empty slot. Leaving her son in the care of her mother, she set out once more to conquer the mountain.