BRASILIA -- In the future that never came, we all live in apartment complexes that float above the ground on concrete stilts -- which is fine, since we no longer need the ground, except to commune with it in zones designated for communing.

We do not walk. We drive wherever we are going, or we take the bus, because the motor vehicle is the transportation mode of the future. The roads are scientifically plotted with cloverleafs and underpasses so that we are not inconvenienced by messy stoplights and intersections. We do not have traffic jams. We glide to our destinations, which are logically identified by numbers and letters. None of this old-fashioned "Broadway" or "Main Street." We take WS-2 to Block 303-S.

Everything is scientifically plotted. Everything is of a piece. We do not think of "cozy" or "variegated" as proper concepts of urban design. Our neighborhoods all look alike, but we don't care. We understand at some deep, deep level that form really does follow function, that less really is more. God is in the details. We have designed -- literally designed -- the brotherhood of man.

In the future that never came, we all live in Brasilia.

It has been three decades since this gleaming city was scraped out of the hard red dirt of Brazil's central plateau. Back then the United States wasn't the only nation in the hemisphere that looked out and saw limitless horizons. A titan was rising in the south, a future Great Power that had just taken a giant stride toward its manifest destiny by building a capital city unlike any other.

The author John Dos Passos was an early believer. In his 1963 book, "Brazil on the Move," Dos Passos described peering down from a small airplane several years earlier and seeing the new capital under construction:

"Suddenly the road appears again. It's a paved road now with traffic on it. Crossroads. Roads in every stage of completion. Cars, trucks, jeeps, buses move back and forth. The plane skirts a long ridge that bristles with scaffolding, concrete construction, cranes, bulldozers, earthmoving machinery. A file of dump trucks parades down the center... . 'Brasilia.' "

He came back later -- after the April 1960 dedication ceremonies -- and found that pedestrians were in constant danger of being smeared because so little provision had been made for sidewalks and crossings. He worried that economic and social distinctions had already begun to bleed through the thin overlay of egalitarian concrete, and that the "routine monotony" of the apartment blocks would prove a bit depressing.

But still, Dos Passos believed in the idea of Brasilia. Now as then, Brasilia is less a city than an idea, dated but still startlingly pure.

It is also a cultural wasteland, a fabulous place to raise children, an end-of-the-road frontier outpost, a magnet for spiritualists and cults, a growing metropolis with a degree of economic and racial segregation that would make a white South African blush, a workaholic's paradise, a tennis player's Valhalla, the ultimate museum of modern architecture ... and the world's preeminent ruin-in-progress.

A brief history is in order. Brasilia had been a notion since Brazil became an independent country in 1822, but it took Juscelino Kubitschek to give it form. Kubitschek, president during the 1950s, decided the time had come to realize the old dream of a new capital in the interior, one that would drain some of the steam out of the haughty coastal cities of Sao Paulo and Rio de Janeiro and begin to open up the vast hinterland.

Kubitschek was looking for a design, a feeling for his new capital that would point the way toward Brazil's sure-to-be-glorious future. And he wanted it built last week. "Fifty years in five" was his slogan.

Then, the story goes, Lucio Costa had a dream.

Costa, a well-known city planner, saw in his dream a city shaped like a jet, with sleek fuselage and swept-back wings. His vision was chosen in a competition, and Oscar Niemeyer, a leading proponent of the minimalist, glass-and-concrete architectural orthodoxy of the day, was picked to build it.

What emerged is an amalgam of monumentalism, utopianism -- Niemeyer was a longtime communist -- and science fiction, dotted with some beautiful buildings.

"The thing about Brasilia," says Ken Love, "is that it's so logical, so absolutely logical. Once you get used to it."

Love is sitting in a pleasant garden behind the Canadian Embassy, along with a group of about two dozen other Brasilia-based expatriates who are glad to explain to a visitor how one comes to terms with such an uncompromising environment.

Love, who hails from a little town near Winston-Salem, N.C., has lived in Brasilia for 19 years. If anyone has earned the right to sing the city's praises, Ken Love has.

His story, like those of so many Brasilia old-timers, is a frontier tale. As he tells it, he was working for a U.S. defense contractor at an underwater tracking station on Ascension Island in the south Atlantic -- this was in the late '60s -- when he and two buddies read an article in Outdoor Life magazine about a diamond find in the coastal state of Bahia. They quit their jobs and struck out for Brazil to make their fortune.

The diamonds, theoretically, were buried under several feet of silt at the bottom of a number of remote rivers and streams in the south of Bahia. They picked their stream, floated a barge in the middle of it and went to work, with Love underwater in scuba gear tugging around a big hose that sucked up the silt, which was then sifted for diamonds.

No diamonds were found, and Love's buddies went home to their wives. But Love decided he liked Brazil and heard there were opportunities in Brasilia. He arrived -- "I saw dirt and dust, and I said, 'There's a future here' " -- and set up a hi-fi repair shop, which wasn't diamonds but was a living.

He began to take an interest in natural foods, one thing led to another, and now he is the owner of Ken's Kitchens, a chain of three successful natural-food restaurants.

He went home for the first time in 19 years last May and is thinking about giving North Carolina another try. But just the thought of leaving gives him saudades, a wonderfully evocative Portuguese word that means wistfulness and longing. "I love it here," he says.

"The first thing you have to understand," he says, "is that everything is in relation to the bus station."

Lucio Costa's fuselage and wings extend from the central bus station, the only place in town that has even a remotely urban feel, insofar as commerce, bustle, noise and the presence of pedestrians help define "urban." The bus station is Brasilia's ground zero.

Spreading east, toward an artificial lake -- toward the tip of the jet -- is an esplanade flanked by identical boxlike buildings that house various government ministries. The great lawn culminates at the slim twin towers of the Congress. Stretching back toward the tail is a series of public monuments and icons, most notably a television tower that is lighted at night to suggest something out of "The Jetsons."

Moving out along the wings is a sequence of "sectors." In the South Wing, for example, one first encounters the South Hotel Sector, where, logically, all the hotels are clumped. Nearby is the South Diversions Sector, where fun, such as going to the movies, is allowed to take place. Then comes the South Commercial Sector. Then begin the residential sectors, which are numbered in a progression that seems more complicated than it has to be. Suffice it to say that sector 101-S is a lot closer to sector 701-S than it is to sector 107-S, and anyone who lives here can tell you that.

The North Wing, of course, is designed as a mirror image of the South Wing.

The residential neighborhoods along the wings are all made up of apartment blocks and all look basically alike.

"But everybody knows that the Brazilian congressmen live in 302-N," Ken Love says. Around the pool at the Canadian Embassy, someone else chimes in that "the American diplomats all live in 113-S." Somebody else notes, "And the British in 403 ..."

It is a pleasant gathering, a Friday night ritual for habitues of the Canadian "pub." Kids frolic, grown-ups have a few beers, everyone enjoys the rich colors and the cool breezes of a Brasilia sunset, and then ... and then everyone goes home.

Weekends in Brasilia are deadly. The most exciting place to be on Friday evenings is the airport, where politicians and bureaucrats engage in a fall-of-Saigon scramble for the last flights to Sao Paulo, Rio de Janeiro, anywhere.

For those with families, there are swimming pools and neighborly cookouts to fill the weekends. For those whose tastes are more rugged, gorgeous hills and spectacular waterfalls are within an hour's drive. For those who play tennis, there are hundreds of courts.

But social life is moribund. And cultural life? "Well," says Sylvia Fonseca, "we don't really have a cultural life."

Fonseca goes back even further than Ken Love. She was born here in 1960, dooming her always to be no older and no younger than the official age of her native city -- a true daughter of the New Brazil.

Fonseca's father was one of the thousands who came here in the late 1950s and "saw a chance to get rich" helping to build Brasilia. He bought a truck in his native Minas Gerais and drove it here to help haul construction materials around. His route kept taking him past a makeshift school for the sons and daughters of the laborers, where one of the teachers caught his eye. They married, and Sylvia Fonseca is the result.

"This was a good place to grow up," says Fonseca, who now works for the environmental ministry. "But this is a city to study and work in, nothing more.

"I lived in Rio for three years when I was in university, and people are very different there. They don't think about work. People would come to class in their bikinis. If it was a nice day, they would take off the afternoon and go to the beach. Here, people work until 7, 8 at night."

Fonseca is single. "I meet friends at bars and restaurants, and there are a lot of mixers for new arrivals. Not that much to do."

Then she brightens. "The design of the city is very good, though, especially to drive. There are never any traffic jams. If I want to go home for lunch, I can."

The Old New City There is a sadness about Brasilia, a feeling that both City and Idea are crumbling inexorably into ruin.

Flanking the bus station are the North Diversions Sector and the South Diversions Sector, which consist of mirror-image shopping and entertainment centers. But the mirror is cracked. The north complex is new and cheery, a place to buy expensive baubles and eat boutique food. The older south complex is like a set for the movie "Blade Runner."

The concrete walls are chipped and discolored. Gloomy passageways lead past secondhand stores, cheap luncheonettes and massage parlors. Teenage boys gather nervously in front of the sad little X-rated movie house, daring each other to go inside. At night the place is cruised by transvestite hookers who prey on innocents from the North Hotel Sector, just across the road.

Not far away, Niemeyer's glass-roofed cathedral is still a soaring, inspiring piece of architecture -- but the lawn nearby is choked with weeds. All the great lawns are crisscrossed with well-worn footpaths, the people's revolt against a city that denies them a place to walk. The thousands of would-be shade trees are stunted little things, the outcome of a miscalculation: Brasilia's stingy soil can barely be coaxed into yielding grass, much less trees. After 30 years, the city still has the immature feel of a brand-new subdivision.

Back at the bus station -- everything leads back to the bus station -- the breakdown of the Idea is evident. Here there are people, all right: street vendors, newsboys, harried pedestrians. But at night they all get on the bus and go home, miles outside the city, to what amount to townships where most of the capital's nearly 2 million people must live.

The de facto segregation is a matter of economics. There is a limited amount of housing in the jet-shaped "pilot plan" area, and the people who can afford it tend to be white-collar bureaucrats. The city, by law, is ringed by a wide green zone of rolling hills. So the working class and the poor live at least 15 miles away on the other side of the hills, out of sight, in places like Planaltina.

There is nothing of the future in Planaltina. It is just another poor Brazilian town, with dirty streets and makeshift dwellings. As usual in Brazil, the poor are disproportionately black. The capital of a nation whose leaders get misty-eyed talking about the Brazilian "rainbow" of racial harmony is marred by an ugly wash of apartheid.

Near Planaltina is a place called the Valley of the Dawn, where on a recent Sunday, groups of people wearing long robes were standing in circles and raising their arms to the heavens in angular poses like those one sees in Egyptian friezes.

The Valley of the Dawn is home to a sect that believes that Brasilia has a privileged place in the universe, spiritually speaking. The idea has to do with its being in the center of the high plateau, in a place where cosmic forces intersect. Other groups have come to Brasilia and set up shop for the same basic reason, but the Valley of the Dawn is the most conspicuous, a kind of mystical theme park. A 30-foot-high plywood Jesus competes with Coptic crosses, Masonic eyes and a miniature pyramid, all arrayed around a giant baptismal pond.

Back at the bus station, an entrepreneur with an apparatus made out of a broom handle and a jar of liquid in which several small troll dolls are immersed offers to tell your fortune or improve your love life... .

It Is What It Is From city of the future to window on the unknown. Yet in a smug, knowing postmodern world, there is a rare purity about Brasilia. There is nothing cute about the place; it does not mock itself, does not wink. Brasilia is what it is. And there are no traffic jams.

Costa and Niemeyer, both in their eighties, rarely talk about the place publicly anymore, although both are still consulted about proposed additions and modifications. Efforts to breach their walls of secretaries and aides were unsuccessful. Niemeyer was quoted not long ago as saying that Brasilia was never supposed to create a New Man, never intended to erase Brazil's monumental inequalities; that those who deplore misery "won't resolve it on the drawing board."

He lives, by the way, in Rio.