Chivay church is pictured on the main square, in front of a giant crucifix carved into the hillside of the Colca valley, March 13, 2005 near Chivay, Peru. The Colca Canyon is the world's deepest, more than twice that of the Grand Canyon. (Jim Dyson/GETTY IMAGES)

The colonial square in Tuti was empty, and the church I’d hoped to visit was locked. It was the four-day Festival of the Cross in May — not, apparently, the most pious of holidays — and everyone was drinking at an arena on the edge of town. I went along.

A spray of colors lit up the sleepy brown countryside. The women wore long floral skirts, handwoven shawls and patterned hats studded with mirrors. The children were wrapped in striped wool blankets. Musicians with horns and drums were scattered through the crowd, playing catchy folk tunes, and people danced in circles, repeatedly pulling me in. The chicha, or corn beer, flowed generously. An old man insisted that I try a shot of herb-infused spirits, which he poured from a plastic soda bottle.

All around the arena, spectators sat with their legs dangling off the wall, watching the bullfights. Men would drag each bull into the ring, then circle it and snap red-and-yellow capes to provoke a charge. If one animal failed to play, the crowd shouted for another, and the dusty charade began again.

Behind them, Peru’s Colca Valley, with its checkered green fields and the Colca River coursing between jagged Andean peaks, unfurled dramatically. Agricultural terraces, some dating to the 11th century, line the hillsides, seeming to stitch together the rugged scenery. Low villages such as Tuti slip into the landscape, almost unnoticeable from afar. All that stands out are the white churches, the valley’s three-story skyscrapers, which I had come to see.

I structured my visit to the Colca Valley around churches largely as an excuse to visit the towns. There would have been no other reason to turn down the dirt road into Tuti. The region is better known for its spectacular setting, with one of the deepest canyons in the world ringed by mountains. Tourists come by bus from Arequipa to hike, soak in the hot springs and see the giant condors.

The villages add cultural and historical depth. After the Spanish conquered the Colca Valley in the 16th century and grouped its scattered residents into 24 towns (17 of which survive today), the outside world left it alone for another 400 years. The region came to international attention only thanks to a National Geographic expedition led by Robert Shippee and George Johnson, whose 1934 article about it was headlined “A Forgotten Valley of Peru.”

It wasn’t until the 1970s that the area got a major road connecting it to Arequipa, Peru’s second-largest city, 100 miles away. Previously there had been little contact with the rest of the country, with goods transported by mule or slow truck. Today, it’s a stunning four-hour drive from the city, past bare volcanic plateaus and snow-capped peaks. At 13,800 feet, a cafe serves fresh coca tea for altitude sickness. Most of the area is a preserve for vicunas, graceful, long-necked animals related to llamas, which graze on the parched grass near the road. The land becomes greener as you descend into Chivay, the regional capital in the south of the valley.

Tourism has come to the Colca Valley only in the past 25 years, and it’s still difficult to get here independently. Renting a car from Arequipa is expensive, so it was smarter for me to travel with an organized tour for $45, which covered transportation and a night in a hotel. Rather than join in the group’s activities, though, I split from them in Chivay and explored on my own with a translator named Roberto. Taxis wait in the main square and can be hired for a negotiable price. Roberto got us one for about $50 for six hours, and we set off for Sibayo, 12 bumpy miles away.

What’s most striking about Sibayo is that it exists at all. Crouching beside gently sloping mountains and a bend in the Colca River, it looks as it did four centuries ago. Low buildings with thatched roofs made from native ichu grass line the grid of cobblestone streets, and red- or blue-painted doors are the rare pops of color. Many houses are abandoned; the tidy square is quiet. Locals carrying woven sacks occasionally pass through, but most live in the adjacent New Sibayo.

Of the nine towns that I visited in two days, Sibayo was the best preserved. Most buildings in the others have tin roofs and plastic signs.

Angel Guillen, an architect who has worked on restoring some of the valley’s 15 churches, says that residents and the town’s leaders have protected Sibayo. “These people are the proudest in the valley and value the town’s heritage,” he says. Community work is common in Andean villages, and each autumn, Sibayo’s residents hold a festival to replace the thatch on the roofs and reinforce their wood frames.

The main activity in the town is the restoration of the church of Saint John the Baptist. Crowning the square, the white stone building dwarfs everything around it. When I visited, men were climbing on one of the twin bell towers, and after Roberto and I called up to them, a worker named Felipe came down to show us around. The interior looked bare: Scaffolding covered the ornate wood-and-gold altar, and the niches were empty of statues, which were being restored elsewhere. But there were vases of fresh flowers, left by the 100 or so congregants who still attend services.

Outside, Felipe pointed to red drops on the step of the front entrance. Before Easter, he said, villagers had sacrificed a llama nearby, then dribbled its blood here as an Inca offering to Pachamama, Mother Earth. Inca and Catholic influences mix in many Peruvian churches, which were often built on older sacred sites and hold services in the indigenous Quechua language. Carvings and murals incorporate elements of nature, such as the flowers that embellish the doorway in Sibayo. Looking for these Baroque Andean elements becomes a sort of scavenger hunt: a sun and moon in the ceiling, corn carved on an altar or a mountain-shaped robe for the Virgin Mary.

It doesn’t take long to see why Peruvians so revere Mother Earth: Her capricious majesty imbues life here. Just across the river from Sibayo is Callalli, a town distinguished by its spiky crown of volcanic rock formations, nicknamed “the castle”; such whimsical shapes dot many nearby mountainsides. The valley is intrinsically connected to the volcanoes: Local myth says that the region’s ancient inhabitants, the Collaguas, came out of one. Volcanoes have also given the region rich soil — for quinoa, corn and potatoes, but also for earthquakes and landslides.

Tremors have repeatedly shaken the valley’s churches. Saint John the Baptist, like many, had already been deteriorating when a 2001 earthquake cracked the roof and weakened the structure. Repair work, funded by the Spanish Agency for International Development Cooperation and the World Monuments Fund, has been steady but slow. It took two years to fix the roof, and indoor work will continue for at least another two. Conservationists hope that restoring and maintaining the valley’s churches will both give locals a sense of ownership and draw tourists, bringing in a little money.

Yanque’s early-18th-century church is in better shape, largely because people visit and donate money. Located on the main road to the famous Cruz del Condor, a popular viewing spot for the giant birds, it’s on the tourist route, with a little woven-goods market and a museum. Like Sibayo, the town has thatched-roof buildings and a manicured square, but here women in Andean garb clapped and danced in circles for the tourists. It felt both artificial and real after the festival in Tuti. There, dancers hadn’t played to a crowd; in Yanque, they got spare change for looking picturesquely traditional.

When we pulled into the town at dusk after the buses left, though, Yanque seemed more itself. Another Festival of the Cross celebration paraded around the square, a ragtag procession with string instruments and firecrackers. Settling down, the town was as Shippee had described it in the 1930s. “The feeling of contact with the outside world was gone,” he wrote. “There was no sound but the gurgling of water in the tiny channels that split the deserted streets.” The sun, fallen behind the mountains, cast a purple mist over the church’s carved facade, which towers over the square.

It’s hard to imagine that the valley once needed such large churches, or so many of them. The roughly 70,000 people who lived here at the time of the Spanish conquest could have filled them, but the structures clearly demonstrated power as much as religion. Initially covered with murals, they grew almost oppressively Baroque as the empire became richer. In the restored church in Maca, for instance, a massive gold altar glints with mirrors. To Inca farmers, the churches must have looked like spaceships.

Dating to the late 16th century, Madrigal’s Saint James is one of the oldest churches in the valley. It’s a slow 18-mile drive west of Chivay, on a dirt road lined with stone walls, cactuses and lupines. Across the river you can see buses carting tourists to and from their condor watch, but this side of the valley is peaceful. The church was closed when we arrived on a weekday morning, so Roberto asked people at the town office to unlock it. They called over a loudspeaker for the man with the key, who quickly came and ushered us in.

Inside, the church was dusty and dark, with scaffolding once again covering the altar, but close examination proved rewarding. The eucalyptus-and-bamboo roof was elegantly completed, tied together in the original fashion with llama-skin rope. The murals, painted with natural watercolors, were being meticulously restored. The delicate images of flowers, birds and leaves looked more beautiful to me than the showy embellishments in other churches. The keymaster told us that Saint James had once been hung with paintings from the colonial Cusco School, which taught European techniques; perhaps that connection explains its fine-art influence.

He also told us that the tower has the largest bell in the Colca Valley, made of bronze and gold and suspended on thick leather straps. I could barely swing it hard enough to make a ding, but when rung properly, it can be heard across the canyon. Just as it did centuries ago, the sound ripples over thatched rooftops and Inca terraces to the farmers on the hillsides. Except it’s no longer the toll of Spanish rule, but that of a way of life, echoing through the mountains.

Dalzell is a writer and urban historian in New York.