By the 600th stair, I'd outclimbed the heat. Only the rain kept pace, thrown sideways by wind that intensified with altitude on Mt. Kinabalu, a 13,000-foot granite ramp in Malaysian Borneo. With blistered feet and drenched clothes, I should've been miserable. But after weeks in the rainforest below, the chill was a relief.

I'd barely traveled beyond Canada before coming here as a wide-eyed volunteer for a group dedicated to saving the critically endangered Sumatran rhino, an elusive, hairy forest-dweller. But after a month of trekking through dense foliage with my head down, scanning the dirt for dung and tracks, all I knew of Borneo was the ground directly in front of me. I decided to hike up Kinabalu for a wider view.

As I climbed, holding fast to the guide ropes, I crossed several distinct vegetation zones, each home to plants and creatures found nowhere else. At lower elevations was the Rafflesia keithii, a fleshy, three-foot-wide flower that takes two years to blossom but withers in days. Slightly higher lived carnivorous pitcher plants capable of digesting rats, and higher still I saw earthworms as long as my leg, their only predator an equally nightmarish leech. To climb Kinabalu was to witness a transition so radical that it was hard to imagine the base and peak as part of the same mountain.

Proof of their union, however, was the slick, coiled, five-mile trail connecting the bottom to the top. At least 600 stairs more and I stepped onto Kinabalu's summit, described by an early explorer as "inaccessible to any but winged animals." But there I was, elated despite cold rain and thick clouds blocking the vista. Perspective wasn't a wide horizon, I realized then, but a series of encounters: the long call of an orangutan in the canopy, clouds shifting like mist wiped from a window, a rhino print deep in the mud. The kind of clarity that, like the Rafflesia, blooms briefly and is gone.