Our Jeep bounces around a tight bend in the River Gorge, and suddenly the rock walls fall away, revealing a hidden valley straight out of a fairy tale. A dozen or so jagged mountains rise up 6,500 feet from a lush, 15-mile-long pasture that's split by a chalky green river. I've been searching for a place like this for more than a decade, and now that I've found it I'm buzzing with anticipation. I fling open the door before the vehicle has even stopped rolling and jump onto the grass. My climbing partners, Jared Ogden and the famed Everest mountaineer Pete Athans, join me seconds later, slapping high fives and gesturing spastically at the peaks. We are the first Western climbers to lay eyes on this particular valley, located at 13,000 feet on the eastern edge of the Tibet plateau in China's Sichuan Province. In fact, only one other Westerner has been to the Jarjinjabo Valley before us.

A landscape like this was the stuff of my dreams – and, I was certain, nothing more – when I started climbing in the mid-1980s. I grew up with the sad impression that I had missed out on mountaineering's golden age – the time up through the 1950s, when most of the world's greatest peaks were conquered: Nanda Devi, in India, by Eric Shipton and H.W. Tilman in 1934; Mount Everest in 1953 by Edmund Hillary and Tenzing Norgay; K2 in 1954 by a team of Italian climbers.

But one of mountaineering's best-kept secrets is that there are thousands of virgin peaks, many as tall as 23,000 feet, in places like Pakistan, India, Myanmar, Bhutan, and China. The truth is, the golden age is still very much alive. And the Jarjinjabo Valley, whose most tantalizing features are Janmo and Jarjinjabo, two 17,000-foot granite spires, is breathtaking proof.

Our team was on an expedition sponsored by the gear and clothing manufacturer The North Face. When we arrived at the airport in Chengdu, Sichuan's capital, in August, we were met by Zhang Jiyue, a fun-loving 41-year-old Chinese adventurer who would serve as our guide and outfitter. We loaded up two jeeps with food and equipment and headed west for the Jarjinjabo Valley, 300 miles away.

Three days later we pulled into the valley, and we were immediately surrounded by a crew of hyperactive, curious boys. Most of the 60 or so families living here are nomads who move camp a few times a year. About ten families, though, have set up a small permanent village of wooden huts near Zhopu Lake. In addition to herding yaks, they grow crops of barley and potatoes. The village mayor, a stringy, wrinkled man named Chedzi, welcomed us with handshakes and friendly slaps on the back.

We spent the first few days acclimatizing to the elevation by hiking around the valley and visiting the locals in their smoky yak-hair tents. They offered us tsampa (roasted barley flour) and yak butter tea. Wealso explored the Zhopu monastery. Built in 1260, it's one of the few on the plateau not completely destroyed by the Chinese in the late fifties.

The prevailing wisdom says you need a day to acclimatize for each 1,000 feet of elevation gain, but after just three days our curiosity about those granite spires got the better of us. We found a trail leading through the old-growth forest in the general direction of Janmo and Jarjinjabo, and all of us were soon sucking wind – including Pete, who has summited Mount Everest seven times. It took us close to two hours of hard slogging before we emerged into a small hanging valley with a crystal clear brook coursing through it. Janmo and Jarjinjabo rose straight ahead. If these spires were located anywhere else, say in Patagonia or along the Baltoro Glacier in Pakistan's Karakoram range, they would undoubtedly be famous...and long since climbed.

Centuries before Tibetan Buddhism emerged there was a shamanistic religion called Bön – in which certain geological formations were considered deities. Bön survives today in a few isolated spots. In the Jarjinjabo Valley there is a myth, likely of Bön origin, that the mountains are actually living characters. Their story goes like this: Jarjinjabo and Janmo were husband and wife. Jarjinjabo left the valley to go on a pilgrimage to Lhasa; Janmo had an affair with another peak and gave birth to several children before Jarjinjabo returned. The smaller surrounding rock towers are those children. I wanted to climb the whole family.

Of the two towers Janmo (the unfaithful wife) is the more slender and aesthetically pleasing. It's also slightly shorter than Jarjinjabo, so we made a plan to climb it first. We would start out in the morning, but we couldn't wait that long to test out the granite. The three of us have climbed granite in just about every corner of the world, including Pakistan, Baffin Island, and Irian Jaya, and when we laid hands to the stone we were shocked. "This is some of the best rock I've ever seen," Jared said as he scrambled a few feet up the bottom of Janmo. The rough brown granite is infused with quartz crystals that make excellent footholds, and, unbelievably, there are no loose flakes.

The next morning high cirrus clouds with mare's tails were blowing in from the southeast. "The good weather looks as if it's on its way out," said Pete as he handed me a steaming mug of coffee. We wasted no time in our preparations; two hours later I was standing next to Jared at the base of Janmo, belaying Pete up the first pitch. He jammed his hands and feet into the vertical crack and shuffled his way up, stopping every ten feet or so to place a protection device and then clipping his rope to it with a carabineer. (This is called free climbing.) About 120 feet off the ground Pete called down, "Off belay." Soon the rope was tugging on my harness, so I followed Pete's lead, trailing a second cord for Jared, who would come up last. As I scaled the pitch with the rope overhead I removed the devices that Pete had placed in the crack. In this manner we were able to climb the spire without physically altering it.

"One of the best pitches of my life!" exclaimed Pete as I high-fived him at the belay. Straight above, a six-foot roof stuck out directly over our heads. From the bottom we had seen that this overhang would likely be the crux of the entire route. I was intimidated, but this was exactly what I'd come for: a test. I learned back in high school that climbing is about trying to make your life as difficult as possible. In this sport you literally hang by your fingertips, and the cost of screwing up could be serious injury or death. The intensity is something I crave, like a drug.

The first few moves off the belay required splitting my legs between the walls of an open book. As I inched my way out under the roof, my weight was almost entirely supported by my arms. It's precisely at this point, when you're most likely to fall, that you have to stay the most calm and collected. So I took a few deep breaths, then swung my leg onto a small quartz edge. With my right hand locked into the coarse granite crack, I reached around the lip with my left hand looking for a slot. When I felt my hand settle deep into the crack, I flexed the muscles in my forearm, creating a hold known as a hand jam. It was a tough move (rated 5.10 on a scale of 5.1 to 5.15), especially considering the altitude (over 16,000 feet). With my left hand locked securely in the crack, I shook out my other arm and released my anxiety with a yell that echoed off the surrounding rocks.

By afternoon most of the 1,200-foot wall was below us. We were huddled on a small ledge underneath a 100-foot pinnacle – the very tip of the formation. But the only way to reach Janmo's highest point would be to drill a ladder of bolts up the blank granite. Rock walls are often conquered with the drill, but in this case we agreed it was unjustified. We wanted to leave the rock as nature had created it rather than drill into it so we could say we'd stood on the very top.

The storm that had been threatening all day finally hit as we finished our last rappel back to the ground – and it stranded us in camp for five long days. When it finally broke we set off toward a 2,000-foot buttress dropping off the left side of Jarjinjabo's east face. An alpenglow lit the wall, revealing every nook, cranny, and pocket. With numb hands we picked our way up the impeccable granite, following a circuitous path between a series of tricky minarets. After 12 hours of continuous climbing Jared led us over a final overhanging headwall and up to the 17,200-foot summit.

Unlike that of Janmo, the top of Jarjinjabo is a plateau several hundred feet across with a small snowfield covering it. We scrambled onto the highest boulder, shook hands, and built a small cairn. "Check out that no man's land back there," said Jared, pointing off the backside to where snow-covered peaks and purple valleys stretched as far as we could see. The realization that this territory had likely never been trodden by any person, Tibetan or otherwise, struck something deep in my soul. Here's a place where I can explore and climb for the rest of my life and never run out of first ascents – a place where, in many ways, the golden age is just beginning.