In the final push to the 11,000-foot summit of Monte Perdido in the Spanish Pyrenees, climbers face a treacherous, half-mile-long incline of snow and ice that corkscrews like an Olympic luge track along a sheer rock drop-off.

The perilous slope is aptly named La Escupidera—the Spittoon. "It's very steep and tilted sideways, so if you slip you get spit down the cliff," explains Rafael Yuste, an HHMI investigator and avid mountaineer who negotiated the slope last July. By one local news account, some 60 people have fallen to their deaths here in the past 30 years.

There were times going up "when I didn't think I was going to make it—I thought 'this is going to be the end of Rafa,'" he recalls, still shivering at the memory. "I was dead tired; my heart was beating out of my chest and I thought, 'I'm going to fall from exhaustion or have a heart attack and slide off the cliff.'"

Traditionally, mountaineers allow two days to scale Monte Perdido (Lost Mountain), stopping overnight at a mountain hut before making the final ascent the next day. In the morning, they start out fresh and make the ascent when the snow is still packed hard, and their crampons—metal spikes attached to their boot soles—can get a firm grip.

		Monte Perdido Summit Follow Rafael Yuste as he climbs Monte Perdido.

During the ascent, the weather became threatening. Yuste, a neurobiologist who studies the microcircuitry of the brain's cortex at Columbia University, and his companions—a veteran group of 40-something professionals, mostly Spanish—decided to go up and back in a single day to avoid getting caught in the coming storm.

They reached the bottom of La Escupidera at 3 p.m. Two of the nine-member climbing party had already turned back. "We had been hiking uphill for more than seven hours, it was getting late and conditions were getting bad," recounts Yuste. "The snow turned soft and our crampons didn't work. It was so foggy we couldn't see the summit above us."

The remaining climbers inched upward, hugging the inner wall of the Spittoon as far from the cliff edge as possible.

"Each of us had an ice axe in one hand and a long pole in the other, and we had to plant them both in the snow to keep us from sliding, then take a step and repeat the process," Yuste says. "We had to stop and rest after every 10 steps."

This went on for about an hour until they reached the cold, windy summit, rewarded by a spectacular 100-mile view of the central Pyrenees. After a brief rest, they headed carefully back down the chute-like Spittoon.

As they descended, one of the party fell. The others watched anxiously as he slowly slid toward the edge of the cliff, repeatedly stabbing his axe into the soft snow. "He wasn't going very fast, but he couldn't stop himself," Yuste says. "Finally the axe held. He just lay there, gripping it with both hands."

When their leader went to the rescue, he, too, slipped and fell, slithering toward the cliff, chopping with his axe in vain. Fortunately, he came to a stop, slowly made his way to the other climber, and both rejoined the party.

Twelve hours after setting out, the adventurers returned to the mountain hut, "completely destroyed" by fatigue, but tremendously happy.

"It's hard to explain why we continue to do these crazy things," confesses Yuste. "To reach the peak is beautiful. We feel we have accomplished something really important. Having done it, other challenges in life seem attainable. As in science, you set yourself a high, apparently unattainable goal, and take small careful steps, without losing track of the summit and without being discouraged by the difficulties, until you get there."

Illustration: Ping Zhu