It took Sohrab Khosraviani several stops before he could find the key to his fire temple. A dignified man of 45 or so, an elder of the Zoroastrian religion, he drove first to a home in an old adobe alleyway, but the key wasn't there. He looked in at a second home, but no, it wasn't there either. We got back in his car and careered across a busy street, popped in at a gas station and asked again. Try the school, we were told.

At the school, little boys lined up solemnly, single file, in a courtyard, each allowed to have just one shot with a basketball at a forlorn hoop. They smiled and waved at me, but didn't dare get out of line. The key wasn't at the school, either. Finally, a friend of Khosraviani's came barreling out of a nearby shop in the warren of alleys.

"Injast!" he cried in Farsi, waving a piece of metal about the size of a ruler. "Here!" Smiles all around. Khosraviani triumphantly led the way down yet another winding corridor, this one arched overhead; I felt a bit like Alice rushing through Wonderland. At last we reached a massive door in a mud wall, which opened with a delicious groan when Khosraviani unlocked it with that intriguing key.

We stepped into a peaceful, whitewashed nave with thick, thick walls, all of it lit by one enormous skylight. A smoky scent enveloped us, part wood smoke and part a heavy incense called esfand burning in an urn. Sultry shafts of sunlight illuminated photographs of the recently departed dead lining the room.

This was the Nush temple, a fire temple somewhere off Khalf Khan Ali Street in the Iranian city of Yazd. It was the kind of small place a visitor could never find without the help of a patient man like Khosraviani, a spokesman for the community who had offered to be my guide. Zoroastrians come to worship here, and a fire or incense is kept burning throughout the year.

Even in Yazd, the centuries-old seat of Zoroastrianism, there are those who believe that Zoroastrians worship fire. No, said Khosraviani: "Fire is our symbol of faith, of our thoughts going toward heaven, of the forces of light ranged against the forces of darkness. When we pray, we always turn toward the least bit of light in any dark room."

He opened a second door, to the temple's innermost chamber, the fire pit, which was charred and smoky and dark. We couldn't see any flames, but, he explained, if even one ember is smoldering, Zoroastrians consider that the fire is burning. Khosraviani seemed contemplative. "The prophet Zoroaster teaches us three things," he said. "Good speaking, good thinking and good deeds. This is what we want to accomplish in life, and redeem evil." A lovely creed, I thought, as an incantation against the chaos of modern life.

I had long wanted to go to Yazd. In 1995, I was startled when, as a reporter interviewing a nephew of the Ayatollah Khomeini on my first trip to Tehran, I watched him pull a small sun medallion from around his neck. "You see this?" he said. "This is a symbol of Zoroaster. I am a Muslim, not a Zoroastrian. But I often think we have so politicized our religion that I prefer to remember the religion of old -- how our greatest kings, Darius and Cyrus, were Zoroastrian."

"If you want to find the true Iranians," he said, "go to Yazd."

It's a Silk Road city, one of those places seen by Marco Polo in the 13th century, a city of fire temples and alleyways, kings and old forts. And clay -- every building is made of golden brick or red adobe. Pagoda-like wind towers punctuate the hummocked, undulating roofs of the old houses, cooling the air and circulating it into the city's recesses. Other wind towers guard the domes of what look like bread ovens, but turn out to be clay water reservoirs, so that even the water is cooled.

Perhaps what's essential about Yazd, on a dry plateau more than 300 miles southeast of Tehran, is its improbable presence against the implacable desert climate. The Iranians call Yazd the "pearl of the desert," but as I peered out the window of the airplane from Tehran, the landscape looked more than a little lunar. Visible in the desert below as we approached Yazd were craters marking the qanats, the underground irrigation canals.

Old Yazd is an ancient labyrinth and new Yazd is a contemporary assault. Next to the 12th-century mosque, there's a lively Internet cafe, and digital weather signs flash at the snarled intersections of this sprawling city of half a million. There are smog alerts -- each morning a light blanket of industrial pollution rises from scores of factories.

And yet modernity is only a smoky breath on Yazd's pre-Islamic past. This is where the last Zoroastrian monarch, Yazdegerd III, held out until 636 A.D., when the followers of Allah scattered the Zoroastrians like dust in the wind. The Zoroastrians take their name from the prophet Zoroaster, also known as Zarathustra, who preached one of the world's earliest monotheistic creeds. Scholars place his birth -- if he was even one person -- between the 10th and 6th centuries B.C., in the northwestern corner of Iran. He held that all the elements -- earth, wind, fire, water -- were sacred, but especially fire. At its height, Zoroastrianism reached from Turkey in the west to as far east as China. It strongly influenced other great religions, including Christianity and Judaism, especially their concepts of the afterlife.

With the Islamic conquest in the 7th century A.D., most Zoroastrians converted to Islam, some were killed, and many fled to India, where they are still known as Parsis. Today there are only 30,000 Zoroastrians left in Iran, a country of 66 million Muslims. Laws discriminate against religious minorities; Zoroastrians emigrate, convert, die. Like people of indigenous faiths in many countries, including our own, Zoroastrians in Iran may one day vanish into memory.

In spite of Islam's dominance, Zoroastrianism runs deep in Iran. Even today, the country operates on the Zoroastrian, not the Western, calendar. And the cherished national holiday called Nowruz, celebrated on the first day of spring, is entirely Zoroastrian: Young Iranians jump over fires, ostensibly to cleanse the body of evil.

One day early in my trip to Yazd, I explored the city's central fire temple, in a graceful white marble building on Ayatollah Kashnai Street. The building has a pretty rose-filled courtyard and looks almost Greek. The fire it houses is said to have been burning continuously at first one site and then another for more than 1,500 years. The shrine, adorned with a picture of Zoroaster in flowing white robes and flaxen hair -- surely an oddity in Iran -- also has divine edicts emblazoned on the walls. This is one of the holiest sites in the religion, and the historic fire is fed with apricot and almond wood by a special tender. But the flames are enclosed behind heavy Plexiglas, giving it all the intimacy of a department store Christmas window. It was much more fun, for me at least, to explore the living, breathing temples tucked away in the back alleys.

The true Iranians. The fact is that by the time of the Arab invasion in the name of Allah in the 7th century, however noble the religion, the Zoroastrian kings had become so corrupt and out of touch with their heavily taxed subjects that much of the population eagerly welcomed the Islamic invaders. The very last Zoroastrian princess, the daughter of Yazdegerd III, dissolved into myth, and I decided to follow her trail, to the place where the mountain is said to have opened its mouth and swallowed her as she fled the conquering horde. On the stark, treeless mountain, a spring gushed forth and a willow sprang up on the spot. Such is the myth of Chek Chek, a name that means "drop by drop" in Farsi, and refers to the princess's tears and the sound the spring makes. The melodious singing of an underground spring in the desert is just one of the things that make Chek Chek beguiling.

To get there, I drove with my friends Bita, a sculptor, and Maziar, a filmmaker, 30 miles from Yazd on flat, dusty roads. Suddenly there was a confrontation between the flat landscape and the rock face of the Karanagh Mountains, badlands so stark that it looked as if the earth had spasmed, spewing molten rock. Halfway up the mountain face was a tiny cliff sanctuary, the site of a willow tree and a shrine enclosing it. It was called Pir Sabz Banu, "the old woman in the mountain." Steep steps ascended to a cool rotunda of green marble, where we could hear the incessant chek-chek-chek of the spring. The tree grew right through the shrine's roof. Around its trunk, pilgrims had tied cloths in supplication to the sainted princess. In the summer, at the scorching end of June, thousands of Parsis from India will flock here. But this day, we had it to ourselves, the canyon walls soaring above us at our back, an eagle's-eye view of the valley below. Bita, who had camped at Chek Chek, told me, "At night it is so dark, and the stars so close, you find yourself reaching out to trace them, or almost plucking them out of the sky."

Earth, wind, fire, water -- Chek Chek is a hallowed shrine to the Zoroastrian myths, but there are even more compelling testaments to belief in and around Yazd: the Towers of Silence. The towers, set on outcroppings of rock, protrude from these plains like broken teeth, each tower lower but much wider than the castle turrets they resemble. We visited every one we saw, all of them now abandoned.

In the evening, as the sun pales to a lemon fire at the edge of the plains around Yazd, the voices of the dead in the Towers of Silence seem loud indeed. For a millennium or more, Zoroastrians brought the bodies of their dead to these towers, to keep the earth pure and to help the souls rise to the infinite. The corpses were wrapped in white shrouds and carried for miles on the heaving shoulders of the living. Drummers drummed and women wailed and water carriers bore vessels to make a pool in the desert at the journey's end to bathe the foreheads of the men who had labored under the weight of the body. At the end of the march, the corpse was handed to the salars, the undertakers who would carry it the last paces to the tower's summit.

"And we saw nothing more of my father," said Sohrab Yazdani, a leader of the Zoroastrian community in Yazd, remembering a day in 1969. "The salars went inside the walls of the tower and unwrapped the body and left it for the vultures." There were thousands of vultures then, blackening the sky, a cacophony of night-colored wings. Within an hour, the salars would retrieve the cleaned bones of the departed and throw them into a central well within the tower. "It is against our religion to pollute the earth with the flesh of the dead," Yazdani explained. "The salars had to live near the Towers of Silence. They were never allowed to come into Yazd."

He paused. "I think the last funeral ceremony here was at least 20 years ago," he said. "Now we hold a special burial at a cemetery nearby. It is not that we are opposed to our own beliefs, but because the vultures vanished from these lands." His smile faded into the darkness.

The Zoroastrians we met in Yazd, though shy, could not have been more welcoming. One holiday, we were invited to a fire temple at dusk. Inside all was a swirl: chanting men in small white hats or kerchiefs, clouds of incense, women in their gorgeously bright head shawls, everyone praying aloud. When it ended there was an explosion of chatter, as the temple-goers passed platters of candy and dried fruit. The crowd seemed wildly pleased to have American visitors.

Our last night in Yazd, we were even lucky enough to make the Jashne Sadeh, a huge, roaring bonfire ceremony marking the 50th day and night before Nowruz, festive as a carnival and attended by hundreds in the courtyard of the main fire temple. The bonfire was fierce and powerful and lovely. Here in the temple with its 1,500-year-old fire, Zoroastrianism seemed nothing if not enduring.

And yet, to get a sense of the Zoroastrian community's fragility, we didn't have to travel very far from Yazd. Zein Abad, some 12 miles away on the road to Taft, is one of dozens of nearly deserted Zoroastrian villages that dot the area. The villages are ethereally beautiful, each one a low earthen hamlet centered on a lone cypress tree. Like everything else, the tree is hundreds of years old. (Cypress is a popular motif found in the silk brocade, or termeh, still woven in Yazd and sold in its bazaars.) The bleat of goats drifts into the deserted streets. Nearly all the homes have been abandoned.

But someone -- a wealthy Zoroastrian from Tehran, it turned out -- was having Zein Abad's empty madrassa, or school, repaired. Next to it was a beautiful fire temple, hung with medieval doors and fairy-tale-size door knockers, traditional ones -- a round knocker for the women's door, a dangling knocker for the men's. I tried one a few times. Eventually, though not exactly summoned, an old man and woman in tattered clothes appeared; the leathery farmer said he once grew pomegranates, hay, eggplants, anything that would thrive in the irrigated desert. "It would be better to be a beggar than to live this life," the old man declared, waving hands as veined as the cracked desert plains. The water has all but dried up in Zein Abad. Fifty years ago, there were 77 families here; now, only 12 aging souls remain. The farmer retreated and came back with his one treasure, an old hand-carved wooden key, nearly a foot long, which opened the doors to some of the empty homes.

The abandonment was much the same in nearby Cham, which had an achingly lovely Tower of Silence, much more isolated than those near Yazd, set in the mountains. The old people congregated in Cham's temple courtyard and invited us for tea, eager for visitors and speaking the rare -- and dying -- Zoroastrian dialect.

The next morning after dawn, Nabati Khoshnasib, one of the elderly women, a burst of color in a pink shawl holding up a pan of ruby-bright pomegranate seeds, offered us the hospitality of her home. Although ashamed of the poor quality of her tin pan, she insisted we take a spoon and dig in. The pomegranate seeds tasted sweet and tart as tears.

I couldn't resist asking. "What will happen when you are gone?" Khoshnasib's son sells dental equipment in Tehran, her daughter is at the university in Yazd.

"This village will be abandoned, like the others," she said simply. It will be the end of history's habitation. Now, the small urn burning incense on a village wall in the early morning light looked almost funereal.

The old women in their neon head scarves gathered in the shade of Cham's fire temple courtyard. Their faces were the parched brown color and texture of the pomegranates left withering on the trees in the town's orchard. And indeed, a pomegranate is one of the metaphors of the faith.

Later, our guide Khosraviani took us back to his home village, called Rahm-Abad, on Yazd's outskirts. "You see the pomegranate, how thin is its rind? And yet inside it holds so many seeds? That is like the faith of Zoroaster," he said. "It is a very delicate thing, but it embraces so many of us."

"But look at the villages," I responded. "What happens when the old people are gone?"

"We are not worried," said Khosraviani. "There are so many people who are really Zoroastrian in their hearts without even knowing it. We are a religion that cares for the earth . . . We will not vanish from these lands."

Friday, our last day in Yazd, happened to be ladies' day at the mosque. The Central Mosque is a magnificent 12th-century shrine. Though it is has nothing to do with Zoroastrians, except perhaps their conquest, its roof and minarets offer a spectacular view of the city's clay labyrinth of walls and wind towers and reservoirs. We climbed and climbed, the wind blustering at our faces and half strangling us with the light chadors we'd been asked to wear over our long coats and scarves. Finally, inside one

of the dark, claustrophobic minarets, we swayed first one way and then another with the wind, before we burst out in giddy relief onto the highest tiny cupola. On the opposite minaret, girls clutched each other in their long black chadors and high heels, and waved to us. Then they tried to proceed the customary seven times around the minaret, their scarves and hems flapping, our scarves flapping in the gusts, until we all felt we were flying in the howling wind.

I looked out at the city, but there was so much sand in the air, and dust, that it was hard to see the horizon, or discern, from this precarious perch, any hint of the Zoroastrians' future in Iran. But I felt sure that for as long as they are there, the past will be preserved by these keepers of the flame.

Jacki Lyden, a senior correspondent for National Public Radio and alternate host of "Weekend All Things Considered," is the author of Daughter of the Queen of Sheba, a memoir.

How To

Traveling to Iran is not reckless, it's fascinating. Iranians love Americans and are keen to overcome the perception left by the embassy takeover of 1979. But there is no American consulate in Iran, and you do have to be alert to the political dynamic, willing to put up with bureaucratic delays, and more dependent on guides than you would be elsewhere. Women are required to wear at least a knee-length coat or shift and head scarf in public, which is uncomfortable in summer. You can apply for a tourist visa from the Iranian Mission at the United Nations (212-687-2020), or have your travel agent go through this long process for you.

To get there: Various tour companies arrange trips to Iran. Try Geographic Expeditions in San Francisco (800-777-8183), Distant Horizons in Long Beach, Calif. (800-333-1240), or Absolute Asia in New York (800-736-8187). You can also call agencies in Iran; many tour people speak excellent English. Pasargad Tour is an especially well-run private company (www.pasargad-tour.com; tel. 011-98-21-205-8833 or -8844 or -8855). Iran Air flies daily from Tehran to Yazd; the journey of 300-plus miles is just $23, round-trip. To stay: In Yazd, the Motel Safaieh is an extremely nice collection of bungalows, rose gardens, pine trees and modern amenities. But bargain over the price -- they will ask for $125 a night, which is absurd in Iran (011-98-351-842-812). The Tourist Yazd Inn is perfectly clean and pleasant, and asks a far more reasonable $50 or so. But again, haggle (011-98-351-47-221). To eat: The tradition of restaurant dining barely exists outside Tehran, so even the loveliest place will offer you kebab, more kebab, and kebab. In Yazd, the Traditional Teahouse, set in a beautiful old bathhouse in the Old City, is not to be missed (011-98-351-670-363). -- J.L.