Ancient Himalayan towers keep their secrets on a walk through southwest China

Writer and National Geographic Society Explorer Paul Salopek’s Out of Eden Walk is a 24,000-mile storytelling odyssey across the world in the footsteps of our human forebears. This dispatch is sent from Sichuan Province in China.

Pengbuxi, Sichuan Province, ChinaThe stone towers of Pengbuxi, a hamlet of yak herders and barley farmers that pools in an 11,000-foot-high valley in the Hengduan Mountains of southwestern China, jut into the sky like colossal exclamation marks.

These towers–four survive, though villagers say there used to be more–are a marvel of ancient engineering. Their spires rise to a hundred feet above surrounding fields. This is a remarkable feat for a freestanding structure made from unworked gray rocks. They have a star-shaped cross-section and eight sides. They taper gracefully towards their tops. What age are they? What was their purpose? Why are they here? These questions are still being debated by Chinese historians. They are largely unknown, and few records exist about the people who built them.

Earlier this year, a teacher friend named Yang Wendou and I hiked across the Hengduan Mountains from south to north. We climbed through Yunnan pine, spruce, fir forests. We skidded down snowy passes in the vicinity of Tibet. We breathed razor-cold air at 15,000 feet. We yo-yoed among ice peaks for 220 miles. We saw many wonders. Perhaps ours was the first foot-traverse of the mountain range, an eastern extension to the Himalaya, in generations. But I can tell you this:

We discovered nothing new about the strange towers of Pengbuxi.

The colossal pillars stand mute sentinel over a remote alpine wilderness. Enigmas from another planet. Megaliths resembling dreams. They still have all the power of a secret.

There are more than four towers.

In the past, scattered across the corrugated highlands of western China, there actually may have been hundreds. Today, only a handful of them are still in existence. Some are reduced to rubble piles. When the Austro-American explorer Joseph Rock passed through the Hengduan Mountains in 1929, for example, he observed “a conglomeration of tall leaning towers” near an old trading outpost called Jiulong. They were gone when Yang and I walked through Jiulong.

There was, however, a new highway tunnel.

The tunnel cored out almost two miles of solid rock near the summit of a 15,000-foot pass. Heavy snows closed the highway. Shen Hao was the tunnel caretaker.

Shen Hao was from the ethnic Yi minority, a middle-aged father of three school-age girls, who spent weeks living alone, marooned in a smoke-blackened hut next to the tunnel generators. He used a woodstove to cook, carried icy creek water in plastic bags, and hung garish yak meat hanks from a ladder in the freezing cold. He was a man who loved solitude and had an immobile face. He said that he had been married to the third-richest family in Chengdu. His sister-in law was enrolled at Harvard. His father-in law wired Shen Hao large amounts of cash via the WeChat app. Shen Hao never asked for this paternal generosity. He refused to work for his family.

“I have everything I need. Things that have price tags? “Things without price tags, like love and friendship, maybe those you can take.”

“Things without price tags, like love and friendship, maybe those you can take.”

The tunnel was like a tower laid on its side: A long, dark, frozen tube from which we emerged, blinking, into a winter landscape so bright it momentarily made me weightless, lifted me, like a snow crystal, off the ground.

Maybe if you burned diamonds you’d get light like that.

The Hengduan Mountains sprawl 560 miles long and 250 miles wide.

A product of the colliding Indian and Asian tectonic plates, the wild range knuckles up in parallel white scarps, each carved by plunging river valleys coursing north-south. The western Himalaya’s ridges run east-west. This is why the region is one of the most biodiverse on Earth. Latitude and elevation intersect to create mazes of high altitude grasslands, chilly conifer forests, temperate Rhododendron thickets and subtropical lowland Savannas. The human picture is even more complicated.

Chinese ethnographers often refer to the mountains of southwestern China as a tribal corridor, a crossroads of antique migrations dating back to the Stone Age. There are pastoralists like the Khampas, eastern Tibetans. There are also members of minority groups like the Yi and Pumi. The descendants of Mongol settlers and Han Chinese settlers. Human diversity complicates research into the history of the Himalayan towers.

“Chinese experts consider that the towers have all been built by Qiang ren (Qiang tribes)” that once inhabited the fringes of the Tibetan Plateau, writes Frederique Darragon, a French cultural preservationist who carbon-dated wooden beams from several towers, producing age estimates spanning 1,200 to 800 years old. “There are many legends about the towers, none of them shedding much light on their possible raison d’etre.”

Darragon believes defense was the likeliest purpose of the extraordinary towers looming over Pengbuxi and elsewhere in the eastern Himalaya. Some structures have slits that can be used for archers. Others speculate that food storage, monuments marking male births and status symbols for the wealthy are some of the reasons.

As for the Khampas prodding groaning yaks around the four giant pillars at Pengbuxi, they simply shrug and amble on.

Yang and I climbed to fairylands of snow-laden spruce and fir. We crossed yak pastures that had been ravaged by the winds. We were engulfed by a white sun.

Near the watery blue shadows of Mount Gongga, at 24,760 feet the tallest peak in Sichuan, we sheltered in the home of Sonam Zeren.

Like other ethnic Tibetan women of her generation in the Hengduan, Sonam Zeren had never set foot in a classroom. She couldn’t read or write. She and her husband raised yaks at high altitude. They had saved for decades to send their boys to university. She continued to work in her village from sunup, renting rooms in the house to medical and traveling teachers. It was difficult to find a solution for Sonam Zeren. My shoulder was her only point of contact. She was a cheerful, tireless blur. Yang and I seldom saw each other during our three days of exhaustion recovery, which was mostly spent at her kitchen counter. When we finally set out on a bracing 12,000-foot morning, she sternly zipped my coat up to my chin. She brought us lunch.

Recently, an earthquake cracked Sonam Zeren’s mountain.

Neither of us speaks Mandarin. I sent her a sad-face emoticon. Within seconds, three circular hand signals pinged back confidently: OK OK OK.

Hieroglyphics fit the Hengduan. In adjacent valleys, there are mutually incomprehensible languages. There are many dialects in the range. Its ridgelines divide accents.

The mountains are a tower. Their name could be Babel.

Professor Luo Xin, an expert in medieval Chinese history at Peking University in Beijing, does not know precisely why the baffling stone towers of the Himalaya were built.

Luo suspects their purpose may have changed across geography and time. But he informs me: “You can find them not just in the Hengduan Mountains but in Beijing.”

A Qing emperor built replicas of the remote Sichuanese towers in his capital, Luo says, to train his troops on siege techniques. This was in the 18th century.

“A few are still there,” he says, laughing. “Nobody really looks at them twice.”

We bunked down with four yak herders. With a melancholic sigh, ice crystals blasted the side their tin house. A bull was found frozen to the bone in the snow outside.

How did shepherds track their individual animals through the immense cosmos of the Hengduan Mountains?

“Oh, we know their faces,” Sonam Badeng explained. “We recognize them.”

Yang and I tottered over a snow pass where mineralized springs gushed water bright as arterial blood. We reached the first lowland roads close to Jiagenbaxiang. The houses of settled Tibetans looked like stone mansions. We’d missed the era of the last black tents by at least 15 years. Friendly pig–hogs were plentiful in the Hengduan Mountains. They trotted up to get their ears rubbed. After less than a minute, it fell onto its back, blissfully sleeping. The towers at Pengbuxi looked like obelisks that had been dropped from a blue ceramic sky.

“They built them to warn of bandit attacks,” said a local businessman named Dengzhu Zhaxi, who was taking his young daughter on a tour of the remote site. “Fire at night, and smoke during the day. Notice how all the towers are line of sight.”

Days later, limping beside the highway between Lhasa and Shanghai, I realized that wasn’t right.

The towers of Pengbuxi are styluses: They were scratching out the stories of our lives on the grand disc of sky that revolves, eternally, above the Hengduan Mountains of Sichuan.

The National Geographic Society, committed to illuminating and protecting the wonder of our world, has funded Explorer Paul Salopek and the Out of Eden Walk project since 2013. Explore the project here.