I CAN’T remember how or why it came to be dawn when I first saw Santa Fe from a bus window. It was my first time in New Mexico, the fulfillment of a long-held dream: to visit the land that had inflamed my imagination when as a teenager I’d read D. H. Lawrence’s paeans to the state.

The desert slowly emerged out of a velvet blackness, became a watery blue, almost the blue of a swimming pool. Then just as we got to the top of the long climb of La Bajada Hill and the Sangre de Cristo mountains sprang into view, the wing of darkness over the earth withdrew, and the true daytime colors began to show, rusty-brown as a cougar’s hide. Ahead, the gaunt lump of the mountains, receiving the first red blush on their faces. At their feet, the mingling of the lights of town with stars of sunlight winking from distant windows.

It’s still one of those approaches, those arrivals, that seems mythical, impossibly grand. The highway reaches away, straight at the mountains, like a long drawbridge into a castle.

Countless people have followed that archetypal ramp into a new life. Santa Fe still holds out a promise of renewal, of exactly what Lawrence was looking for when he came to this area: a place that could change not only one’s external life but also one’s inner, spiritual life. “Touch the country,” he said of New Mexico, “and you will never be the same again.”

What is Santa Fe? A place of healing, since the tuberculosis sufferers started coming over a century ago. A spiritual mini-mecca for a semi-godless age. A sumptuous adobe haven for a few super-rich. A land of hope for thousands of illegal immigrants. A hothouse of talent and IQ, with an extraordinary concentration of Ph.D.’s, and more artists than any American city its size. (According to one report, 39 percent of the city’s economy is generated by the arts and culture.) On and on the list goes. It’s a city of trade and exchange, of markets, built at the crossroads of the old Camino Real and the Santa Fe Trail. Wealthy people fly here from New York to buy their Asian rugs, and opera lovers flock here in summer for the justifiably world-famous open-air productions at the Santa Fe Opera.

But perhaps the greatest draw is still the promise of a spiritual homeland. There are no fewer than four Zen centers, several Tibetan shrines, any number of New Age “institutes,” innumerable churches of all denominations, yoga centers, gurus, teachers, seers, prophets, Sufis, Sikhs, literally thousands of therapists — body, mind, spirit and everything-in-between therapists. This is a city where the wounded come for healing, and seekers come to find.

I’ve been coming to Santa Fe since 1991, and have lived there for the last five years. I’ve developed some predictable preconceptions — there’s the famous tricultural diversity, the celebrated adobe look, and so on. But I still don’t really know it, even though it’s not a big place. A city, like everything on this earth, is constantly changing. Gov. Bill Richardson recently said in an interview that today there’s a new Santa Fe. Many would agree. But how do you measure such a thing? How do you find it?

As Santa Fe celebrates its 400th year of existence, a milestone that will be marked by a year’s worth of events, I decided to let myself be led along a chain of links, and see where it ended up: a kind of treasure hunt, one clue leading to the next. Perhaps as I followed it, I’d even figure out how a British poet like myself ever wound up here.

I FIRST saw the tree a few weeks ago. If I hadn’t been tipped off, I would have driven right past it. It’s no more than 10 feet tall, and you could easily miss the fact that its leaves are made of green plastic bottles cut up to resemble bushy, brilliant foliage, and that its trunk is old tire treads laid out in long, somehow elegant strips. Not only that, it’s in the form of a slender woman, fine and aquiline of feature, standing with her arms outstretched, like a cross between Mother Mary, a supermodel and the crucifix high above Rio.

Three guys happened to be climbing into an old pickup nearby. Did they know anything about what the beautiful recycled tree was doing here, outside a community center in semi-central Santa Fe?

One of the men, with a Stetson and bushy gray mustache, eyed me a second, then said: “Some Brazilian guys from the Institute made it.” He glanced up with a smile. “Sure is pretty what they can do with a tire.”

“The Institute?”

“The Art Institute.”

The day I visited the Santa Fe Art Institute to learn more about the tire tree, a troupe of Native American dancers from around the country, Dancing Earth, had gathered for three weeks of rehearsal. Dressed in elegant evening wear, looking like classical ballerinas at a cocktail party, they were mingling with well-wishers. They use dance to provide a bridge, Rulan Tangen, their leader explained, from the sacred native world of dance to the wider world.

Diane Karp, the Institute’s director, clearly loves the flow of all kinds of creativity that passes through her doors, such doors as there are. The main studios — enormous, beautiful white chambers — flow into one another, creating maximum opportunities for creative exchange. It was she who found two Brazilian street artists and managed to get them here. One of their projects was the tire tree. “Isn’t it great?” Ms. Karp said. “We brought these guys in from São Paulo. They’ve done murals there in the favelas telling the history of the shanties. They were keen to come, so they’re busy working around town, creating graffiti art and recycled art.”

Guerrilla artists?

“Pretty much. We don’t want to turn our kids off art, by trying to bring our ideas to them. It works better the other way round.”

A few streets away, there was another art gathering going on this evening. Swing a tortilla in Santa Fe and you’ll hit an artist. (One reason for this is a living-wage ordinance Mayor David Coss introduced when he was on the city council, which helps artists to support themselves with day jobs.)

Meow Wolf is a young art collective — a pack, as they call themselves. At their last show they wheeled an old Volkswagen into their warehouse space and fell on it. In three hours straight they tore the vehicle to pieces, and made a stop-motion video of the process.

Tonight was “Throwdown” night. One of the artists put out boards and art supplies and piles of “recycled art materials” — a k a junk — and invited members of the pack to assemble pieces on the boards any way they liked. The resulting contained chaoses were surprisingly beautiful. A doll sprouts wings made of shards of wood from a broken palette, looking like a winged cherub. A shoe gets wrapped in rope. Lots of paint is used. And insulating foam. And glue. And wire. And all kinds of everything.

A number of people were drifting through, congregating around the one big old cylindrical gas heater in the middle of the main room. “Yeah,” said one of the crew. “We were bombed. We used to have an old wood-burning stove but someone stole it.”

Is Santa Fe a congenial place to do the art they do?

“Totally,” said Quinn Tincher, alpha voice of the pack. “We’re the only place doing this, so people are very supportive. They donate stuff all the time. Just leave it for us in the parking lot. They know we’ll use it.”

Matt King, another member, added: “And if anyone is into our kind of aesthetic, they tend to join us. People are always coming through town. They find us.”

This summer, to coincide with the latest Biennial at SITE Santa Fe (which promises to be a stunning assembly of animated artwork), Meow Wolf has been invited by the Linda Durham Gallery, a pillar of the art scene for 30 years, to recreate their 16-foot Dome, a geodesic frame completely jammed with old household goods — armchairs, tables, TVs, ovens, everything — suspended in a congealed mass.

SOONER or later, everything new becomes old. But wait long enough, and the old becomes new again. Nearly a century ago, the elders of Santa Fe devised a way to attract tourists: their building code, based on the ancient pueblo adobe style. America’s only ancient mud city began to spread into the 20th century.

What has set Santa Fe apart from all other American cities is not that it is old but the foresight of the decision to make it look old. Santa Fe is a kind of hoax, one that has been so successful, economically, architecturally and culturally, that the reality of its success has overwhelmed the pretense of its origins. It doesn’t matter how it came about; it is the adobe gem we see today.

The same foresight that put Santa Fe on the map for “cultural tourism” in the 1920s continues to keep Santa Fe ahead of the game. Rather than letting the city become a worn-out one-trick pony, initiatives of the past few years to transform it have come to fruition.

One architect of these is Governor Richardson. Thanks to statewide tax breaks, Santa Fe now has a thriving movie industry, with a studio being built just outside town and an in-state crew base of thousands. A new $400 million railway, the Rail Runner, connects Santa Fe with Albuquerque. The city has a whole new downtown section, both the new Railyard and the Triangle District, designed with a neo-industrial look a far cry from the traditional adobe. There’s the magnificent New Mexico History Museum, opened last May, a light-filled multilevel edifice that also incorporates the nation’s oldest continually occupied municipal building, the Palace of the Governors.

Santa Fe still has an extraordinary concentration of artists and scientists, many of the latter based at the Santa Fe Institute; what is different today is that the scientists and artists are actually beginning to collaborate, in complexity experiments that are among the most progressive happening anywhere on the planet. And it is quietly fostering its own green revolution.

“Yes, there’s a new Santa Fe,” the governor said when I visited him in his splendid, hushed third-floor office in the round Senate Building (high, for low-rise Santa Fe). “But it’s one founded on our past. Thanks to the Historic Preservation Board, we’ve done a tremendous job of conserving our history. And now we’re moving into new territory. Above all, we’re becoming connected.”

Alfonz Viszolay operates from an adobe complex on a frontage road south of Santa Fe. In his gravel yard between two large adobe buildings, a few old trucks stand on blocks amid high-tech-looking machines for pollution control, with elaborate tangles of pipes, shining cylinders, lights, dials and switches. There are sculptures made of scrap iron, and newly planted trees. The impression is like a grand Hispanic ranch crossed with a Mad Max pit stop.

With his bushy white mustache and a mischievous twinkle in the eye, Mr. Viszolay, a native of Hungary, has been something of a green pioneer for four decades. “I was getting aware the environment has to be do something,” he said in his charming, accented Hunglish.

Mr. Viszolay’s current baby is algae. With Paul Laur, he uses wastewater to feed algae, pumping carbon dioxide emissions through them to make them grow faster, then harvesting them for biofuel.

“Look at this,” he said, pulling a tarpaulin aside to reveal a gleaming blue race car in a hangarlike wing of his complex. “It runs on bio-ethanol and alcohol. And it’s fast.” He grinned. “We show them what these fuels can do.”

In this new era of sustainability, Mr. Viszolay says he has found Santa Fe to be an ideal place to operate. “There are so many Ph.D.’s here,” he said. “And people don’t worry about Armani suits. You have to be real. There are some of the most brilliant people in the world right here, but you’d never believe it if you saw them. Dirty clothes, old jeans.”

Over the years he has brought in Navajo dancers to bless his projects — a strange but happy conjunction of science and the old ways. “The Indian nation was always clean and responsible,” Mr. Viszolay said. “They don’t make mess like modern America.” Natives and progressives: just what the new Santa Fe is all about.

On a very cold New Year’s morning, I met up with two young artists from Santa Clara Pueblo outside their favorite hangout, the Aztec Café. The place was closed for the holiday, so we went instead to nearby Café Dominic for Earl Grey tea.

Is Santa Fe good for young artists?

“There’s high art here, international art, and rich people to buy it,” said Rose Bean Simpson, who has a scholarship to Rhode Island School of Design. “It could be frustrating if you’re a young artist with a different aesthetic.”

“But that’s changing,” Eliza Naranjo-Morse broke in. “Native art used to be about making iconic gifts for people to take home, and that still exists. But when our parents were younger, people began creating genuine contemporary art, too.”

A major engine behind that evolution has been the Institute for American Indian Arts, a premier national institution for contemporary native art. As the marker of 400 years of European presence arrives, the institute has opened three buildings on its campus south of town, doubling its size and enrollment.

Tremendous changes are happening in the nearby Indian pueblos, too. Most conspicuously, Pojoaque Pueblo a few miles north of town has opened perhaps the biggest resort in the state, Buffalo Thunder. With a spa, golf course, pools, tennis courts and casinos, the development is crammed full of pueblo art. It’s not only a resort but almost a museum.

The inspiration behind it is Pojoaque Governor George Rivera, a talented artist who trained in California and France, as well as at the institute. He took me for a glide around the pueblo’s little empire in his gleaming white BMW. Many of the developments were not only initiated by Mr. Rivera but even designed by him. For example, the new adobe church with a monolithic red stone campanile and six-arch Romanesque portal.

“You’re an architect, too?” I asked him.

“I’m a designer,” he said. “I’m an artist. And we have our own construction company, so if we don’t like something, we can pull it down and do it again.”

A century ago, with American development going into hyperdrive, it might have seemed impossible that Santa Fe, a little city 10 miles from the railroad, could both grow and preserve its character. Yet it happened. Today that city is “at a cusp moment,” said Zane Fischer, cultural columnist of The Santa Fe Reporter, an alternative weekly. “The preservation has happened, and we all have to be eternally grateful to the folks who made it happen. But now we can also pull together all the incredible resources of this city — the centuries of green thinking, the science, the artists, the writers.”

One place attempting to do just that is the new Santa Fe Complex, near the Railyard, an experimental space devoted to collaboration among the arts, science and technology. All the furniture in the large cement-floored main hall is on wheels. “It’s all about fluidity, flow,” said Ed Angel, the complex’s president. “We bring creative people together, but we’re not here to achieve certain results.”

Like an exercise in complexity science?

“Exactly. We don’t want to know the outcome. We’re here to see what happens, that’s all.”

Clearly, much has happened already.

And as for that oddly dislocated British poet who was drawn here, along with thousands of other Europeans? They say Santa Fe has a will of its own. If the town wants you, it will get you and keep you; if not it will eject you. We’re obviously all just unwitting elements in a complexity experiment, one whose outcome is not the point, which we never even knew we were part of. And it’s only just beginning.

IF YOU GO

Santa Fe became the capital of the New Mexico province in 1610, making it the first state capital in the United States to celebrate its quatercentenary. Whether the arrival of armed invaders who “settled” land that had been inhabited for centuries — and put those who objected to the sword — is something to celebrate or mourn is an open question. (Perhaps New Mexico, with its many pueblos, will one day follow South Dakota in changing Columbus Day to Native American Day.) But somehow the Europeans and Indians have muddled through, and the Royal City of the Holy Faith of Saint Francis of Assisi has become the beloved adobe wonder that it is.

In addition to various events the city is planning, many new developments have recently been completed. The Rail Runner Express (nmrailrunner.com), which runs from Belen, south of Albuquerque, now arrives at the Santa Fe Depot several times a day. After many years of planning, building and renovation, the Railyard (railyardsantafe.com), with its complex of shops and farmers’ market (open Tuesdays and Saturdays during warm-weather months and Saturdays the rest of the year), opened in September 2008. Thousands of new students within the state are now studying for different areas of the burgeoning film industry. Green businesses are growing.

On the culinary front, in spite of the recession, new restaurants have opened, most notably a proliferation of chocolateries, and a farm-to-table initiative is thriving. The city is small enough, the region fertile enough, to revive a kind of neo-medieval connection between city and countryside.