The World Trade Centre attack was the defining moment of the year - and will haunt us for decades. Don DeLillo on the terror that overturned history

In the past decade the surge of capital markets has dominated discourse and shaped global consciousness. Multinational corporations have come to seem more vital and influential than governments. The dramatic climb of the Dow and the speed of the internet summoned us all to live permanently in the future, in the utopian glow of cyber-capital, because there is no memory there and this is where markets are uncontrolled and investment potential has no limit.

All this changed on September 11. Today, again, the world narrative belongs to terrorists. But the primary target of the men who attacked the Pentagon and the World Trade Centre was not the global economy. It was America that drew their fury. It was the high gloss of our modernity. It was the thrust of our technology. It was our perceived godlessness. It was the blunt force of our foreign policy. It was the power of American culture to penetrate every wall, home, life and mind.

Terror's response is a narrative that has been developing over years, only now becoming inescapable. It is our lives and minds that are occupied now. This catastrophic event changes the way we think and act, moment to moment, week to week, for unknown weeks and months to come, and steely years. Our world, parts of our world, have crumbled into theirs, which means we are living in a place of danger and rage.

The protesters in Genoa, Prague, Seattle and other cities want to decelerate the global momentum that seemed to be driving unmindfully toward a landscape of consumer-robots and social instability, with the chance of self-determination probably diminishing for most people in most countries. Whatever acts of violence marked the protests, most of the men and women involved tend to be a moderating influence, trying to slow things down, even things out, hold off the white-hot future.

The terrorists of September 11 want to bring back the past.

OUR tradition of free expression and our justice system's provisions for the rights of the accused can only seem an offence to men bent on suicidal terror.

We are rich, privileged and strong, but they are willing to die. This is the edge they have, the fire of aggrieved belief. We live in a wide world, routinely filled with exchange of every sort, an open circuit of work, talk, family and expressible feeling. The terrorist, planted in a Florida town, pushing his supermarket trolley, nodding to his neighbour, lives in a far narrower format. This is his edge, his strength. Plots reduce the world. He builds a plot around his anger and our indifference. He lives a certain kind of apartness, hard and tight. This is not the self-watcher, the soft white dangling boy who shoots someone to keep from disappearing into himself. The terrorist shares a secret and a self. At a certain point he and his brothers may begin to feel less motivated by politics and personal hatred than by brotherhood itself. They share the codes and protocols of their mission here and something deeper, a vision of judgment and devastation.

Does the sight of a woman pushing a stroller soften the man to her humanity and vulnerability, and her child's as well, and all the people he is here to kill?

This is his edge, that he does not see her. Years here, waiting, taking flying lessons, making the routine gestures of community and home, the credit card, the bank account, the post-office box. All tactical, linked, layered. He knows who we are and what we mean in the world - an idea, a righteous fever in the brain. But there is no defenceless human at the end of his gaze.

The sense of disarticulation we hear in the term "Us and Them" has never been so striking, at either end.

We can tell ourselves that whatever we've done to inspire bitterness, distrust and rancour, it was not so damnable as to bring this day down on our heads. But there is no logic in apocalypse. They have gone beyond the bounds of passionate payback. This is heaven and hell, a sense of armed martyrdom as the surpassing drama of human experience.

He pledges his submission to God and meditates on the blood to come.

The Bush administration was feeling a nostalgia for the cold war. This is over now. Many things are over. The narrative ends in the rubble and it is left to us to create the counternarrative.

There are 100,000 stories crisscrossing New York, Washington, and the world. Where we were, who we know, what we've seen or heard. There are the doctors' appointments that saved lives, the cellphones that were used to report the hijackings. Stories generating others and people running north out of the rumbling smoke and ash. Men running in suits and ties, women who'd lost their shoes, cops running from the skydive of all that towering steel.

People running for their lives are part of the story that is left to us.

There are stories of heroism and encounters with dread. There are stories that carry around their edges the luminous ring of coincidence, fate, or premonition. They take us beyond the hard numbers of dead and missing and give us a glimpse of elevated being. For 100 who are arbitrarily dead, we need to find one person saved by a flash of forewarning. There are configurations that chill and awe us both. Two women on two planes, best of friends, who die together and apart, tower 1 and tower 2. What desolate epic tragedy might bear the weight of such juxtaposition? But we can also ask what symmetry, bleak and touching both, takes one friend, spares the other's grief?

The brother of one of the women worked in one of the towers. He managed to escape.

In Union Square Park, about two miles north of the attack site, the improvised memorials are another part of our response. The flags, flowerbeds and votive candles, the lamppost hung with paper airplanes, the passages from the Koran and the Bible, the letters and poems, the cardboard John Wayne, the children's drawings of the twin towers, the hand-painted signs for Free Hugs, Free Back Rubs, the graffiti of love and peace on the tall equestrian statue.

There are many photographs of missing persons, some accompanied by hopeful lists of identifying features. (Man with panther tattoo, upper right arm.) There is the saxophonist, playing softly. There is the sculptured flag of rippling copper and aluminium, six feet long, with two young people still attending to the finer details of the piece.

Then there are the visitors to the park. The artifacts on display represent the confluence of a number of cultural tides, patriotic and multidevotional and retro hippy. The visitors move quietly in the floating aromas of candlewax, roses and bus fumes. There are many people this mild evening and in their voices, manner, clothing and in the colour of their skin they recapitulate the mix we see in the photocopied faces of the lost.

For the next 50 years, people who were not in the area when the attacks occurred will claim to have been there. In time, some of them will believe it. Others will claim to have lost friends or relatives, although they did not.

This is also the counternarrative, a shadow history of false memories and imagined loss.

The internet is a counternarrative, shaped in part by rumour, fantasy and mystical reverberation.

The cellphones, the lost shoes, the handkerchiefs mashed in the faces of running men and women. The box cutters and credit cards. The paper that came streaming out of the towers and drifted across the river to Brooklyn backyards, status reports, résumés, insurance forms. Sheets of paper driven into concrete, according to witnesses. Paper slicing into truck tyres, fixed there.

These are among the smaller objects and more marginal stories in the sifted ruins of the day. We need them, even the common tools of the terrorists, to set against the massive spectacle that continues to seem unmanageable, too powerful a thing to set into our frame of practised response.

Ash was spattering the windows. Karen was half dressed, grabbing the kids and trying to put on some clothes and talking with her husband and scooping things to take out to the corridor, and they looked at her, her twin girls, as if she had 14 heads.

They stayed in the corridor for a while, thinking there might be secondary explosions. They waited, and began to feel safer, and went back to the apartment.

At the next impact, Marc knew in the sheerest second before the shock wave broadsided their building that it was a second plane, impossible, striking the second tower. Their building was two blocks away and he'd thought the first crash was an accident.

They went back to the hallway, where others began to gather, 15 or 20 people.

Karen ran back for a cellphone, a cordless phone, a charger, water, sweaters, snacks for the kids and then made a quick dash to the bedroom for her wedding ring.

From the window she saw people running in the street, others locked shoulder to shoulder, immobilised, with debris coming down on them. People were trampled, struck by falling objects, and there was ash and paper everywhere, paper whipping through the air, no sign of light or sky.

Cellphones were down. They talked on the cordless, receiving information measured out in eyedrops. They were convinced that the situation outside was far more grave than it was here.

Smoke began to enter the corridor.

Then the first tower fell. She thought it was a bomb. When she talked to someone on the phone and found out what had happened, she felt a surreal relief. Bombs and missiles were not falling everywhere in the city. It was not all-out war, at least not yet.

Marc was in the apartment getting chairs for the older people, for the woman who'd had hip surgery. When he heard the first low drumming rumble, he stood in a strange dead calm and said, "Something is happening." It sounded exactly like what it was, a tall tower collapsing.

The windows were surfaced with ash now, blacked out completely, and he wondered what was out there. What remained to be seen and did he want to see it?

They all moved into the stairwell, behind a fire door, but smoke kept coming in. It was gritty ash and they were eating it.

He ran back inside, grabbing towels off the racks and washcloths out of drawers and drenching them in the sink, and filling his bicycle water bottles, and grabbing the kids' underwear. He thought the crush of buildings was the thing to fear most. This is what would kill them.

Karen was on the phone, talking to a friend in the district attorney's office, about half a mile to the north. She was pleading for help. She begged, pleaded and hung up. For the next hour a detective kept calling with advice and encouragement.

Marc came back out to the corridor. I think we might die, he told himself, hedging his sense of what would happen next.

The detective told Karen to stay where they were.

When the second tower fell, my heart fell with it. I called Marc, who is my nephew, on his cordless. I couldn't stop thinking of the size of the towers and the meagre distance between those buildings and his. He answered, we talked. I have no memory of the conversation except for his final remark, slightly urgent, concerning someone on the other line, who might be sending help.

Smoke was seeping out of the elevator shaft now. Karen was saying goodbye to her father in Oregon. Not hello-goodbye. But goodbye-I-think-we-are-going-to-die. She thought smoke would be the thing that did it.

People sat on chairs along the walls. They chatted about practical matters. They sang songs with the kids. The kids in the group were cooperative because the adults were damn scared.

There was an improvised rescue in progress. Karen's friend and a colleague made their way down from Centre Street, turning up with two policemen they'd enlisted en route. They had dust masks and a destination and they searched every floor for others who might be stranded in the building.

They came out into a world of ash and near night. There was no one else to be seen now on the street. Grey ash covering the cars and pavement, ash falling in large flakes, paper still drifting down, discarded shoes, strollers, briefcases. The members of the group were masked and towelled, children in adults' arms, moving east and then north on Nassau Street, trying not to look around, only what's immediate, one step and then another, all closely focused, a pregnant woman, a newborn, a dog.

They were covered in ash when they reached shelter at Pace University, where there was food and water, and kind and able staff members, and a gas-leak scare, and more running people.

Workers began pouring water on the group. Stay wet, stay wet. This was the theme of the first half-hour.

Later a line began to form along the food counter.

Someone said, "I don't want cheese on that."

Someone said, "I like it better not so cooked."

Not so incongruous, really, just people alive and hungry, beginning to be themselves again.

Technology is our fate, our truth. It is what we mean when we call ourselves the only superpower on the planet. The materials and methods we devise make it possible for us to claim our future. We don't have to depend on God or the prophets or other astonishments. We are the astonishment. The miracle is what we ourselves produce, the systems and networks that change the way we live and think.

But whatever great skeins of technology lie ahead, ever more complex, connective, precise, micro-fractional, the future has yielded, for now, to medieval expedience, to the old slow furies of cut-throat religion.

Kill the enemy and pluck out his heart.

If others in less scientifically advanced cultures were able to share, wanted to share, some of the blessings of our technology, without a threat to their faith or traditions, would they need to rely on a God in whose name they kill the innocent? Would they need to invent a God who rewards violence against the innocent with a promise of "infinite paradise", in the words of a handwritten letter found in the luggage of one of the hijackers?

For all those who may want what we've got, there are all those who do not. These are the men who have fashioned a morality of destruction. They want what they used to have before the waves of western influence. They surely see themselves as the elect of God whether or not they follow the central precepts of Islam. It is the presumptive right of those who choose violence and death to speak directly to God. They will kill and then die. Or they will die first, in the cockpit, in clean shoes, according to instructions in the letter.

Six days after the attacks, the territory below Canal Street is hedged with barricades. There are few civilians in the street. Police at some checkpoints, troops wearing camouflage gear and gas masks at others, and a pair of state troopers in conversation, and 10 burly men striding east in hard hats, work pants and NYPD jackets. A shop owner tries to talk a cop into letting him enter his place of business. He is a small elderly man with a Jewish accent, but there is no relief today. Garbage bags are everywhere in high, broad stacks. The area is bedraggled and third-worldish, with an air of permanent emergency, everything surfaced in ash.

It is possible to pass through some checkpoints, detour around others. At Chambers Street I look south through the links of the National Rent-A-Fence barrier. There stands the smoky remnant of filigree that marks the last tall thing, the last sign in the mire of wreckage that there were towers here that dominated the skyline for over a quarter of a century.

Ten days later and a lot closer, I stand at another barrier with a group of people, looking directly into the strands of openwork facade. It is almost too close. It is almost Roman, I-beams for stonework, but not nearly so salvageable. Many here describe the scene to others on cellphones.

"Oh my God, I'm standing here," says the man next to me.

The World Trade towers were not only an emblem of advanced technology but a justification, in a sense, for technology's irresistible will to realise in solid form whatever becomes theoretically allowable. Once defined, every limit must be reached. The tactful sheathing of the towers was intended to reduce the direct threat of such straight-edge enormity, a giantism that eased over the years into something a little more familiar and comfortable, even dependable in a way.

Now a small group of men have literally altered our skyline. We have fallen back in time and space. It is their technology that marks our moments, the small, lethal devices, the remote-control detonators they fashion out of radios, or the larger technology they borrow from us, passenger jets that become manned missiles.

Maybe this is a grim subtext of their enterprise. They see something innately destructive in the nature of technology. It brings death to their customs and beliefs. Use it as what it is, a thing that kills.

Eleven years ago, during the engagement in the Persian Gulf, people had trouble separating the war from coverage of the war. After the first euphoric days, coverage became limited. The rush of watching all that eerie green night-vision footage, shot from fighter jets in combat, had been so intense that it became hard to honour the fact that the war was still going on, untelevised. A layer of consciousness had been stripped away. People shuffled around, muttering. They were lonely for their war.

The events of September 11 were covered unstintingly. There was no confusion of roles on TV. The raw event was one thing, the coverage another. The event dominated the medium. It was bright and totalising and some of us said it was unreal. When we say a thing is unreal, we mean it is too real, a phenomenon so unaccountable and yet so bound to the power of objective fact that we can't tilt it to the slant of our perceptions. First the planes struck the towers. After a time it became possible for us to absorb this, barely. But when the towers fell. When the rolling smoke began moving downward, floor to floor. This was so vast and terrible that it was outside imagining even as it happened. We could not catch up with it. But it was real, punishingly so, an expression of the physics of structural limits and a void in one's soul, and there was the huge antenna falling out of the sky, straight down, blunt end first, like an arrow moving backwards in time.

The event itself has no purchase on the mercies of analogy or simile. We have to take the shock and horror as it is. But living language is not diminished. The writer wants to understand what this day has done to us. Is it too soon? We seem pressed for time, all of us. Time is scarcer now. There is a sense of compression, plans made hurriedly, time forced and distorted. But language is inseparable from the world that provokes it. The writer begins in the towers, trying to imagine the moment, desperately. Before politics, before history and religion, there is the primal terror. People falling from the towers hand in hand. This is part of the counternarrative, hands and spirits joining, human beauty in the crush of meshed steel.

In its desertion of every basis for comparison, the event asserts its singularity. There is something empty in the sky. The writer tries to give memory, tenderness and meaning to all that howling space.

We like to think that America invented the future. We are comfortable with the future, intimate with it. But there are disturbances now, in large and small ways, a chain of reconsiderations. Where we live, how we travel, what we think about when we look at our children. For many people, the event has changed the grain of the most routine moment.

We may find that the ruin of the towers is implicit in other things. The new Palm Pilot at a fingertip's reach, the stretch limousine parked outside the hotel, the midtown skyscraper under construction, carrying the name of a major investment bank - all haunted in a way by what has happened, less assured in their authority, in the prerogatives they offer.

There is fear of other kinds of terrorism, the prospect that biological and chemical weapons will contaminate the air we breathe and the water we drink. There wasn't much concern about this after earlier terrorist acts. This time we are trying to name the future, not in our normally hopeful way, but guided by dread.

What has already happened is sufficient to affect the air around us, psychologically. We are all breathing the fumes of lower Manhattan, where traces of the dead are everywhere, in the soft breeze off the river, on rooftops and windows, in our hair and on our clothes.

Think of a future in which the components of a microchip are the size of atoms. The devices that pace our lives will operate from the smart quantum spaces of pure information. Now think of people in countless thousands massing in anger and vowing revenge. Enlarged photos of martyrs and holy men dangle from balconies, and the largest images are those of a terrorist leader.

Two forces in the world, past and future. With the end of communism, the ideas and principles of modern democracy were seen clearly to prevail, whatever the inequalities of the system itself. This is still the case. But now there is a global theocratic state, unboundaried and floating and so obsolete it must depend on suicidal fervour to gain its aims.

Ideas evolve and de-evolve, and history is turned on end.

On Friday of the first week a long series of vehicles moves slowly west on Canal Street. Dump trucks, flatbeds, sanitation sweepers. There are giant earthmovers making a tremendous revving sound. A scant number of pedestrians, some in dust masks, others just standing, watching, the indigenous people, clinging to walls and doorways, unaccustomed to traffic that doesn't bring buyers and sellers, goods and cash. The fire rescue car and state police cruiser, the staccato sirens of a line of police vans. Cops stand at the sawhorse barriers, trying to clear the way. Ambulances, cherry pickers, a fleet of Con Ed trucks, all this clamour moving south a few blocks ahead, into the cloud of sand and ash.

One month earlier I'd taken the same walk, early evening, among crowds of people, the panethnic swarm of shoppers, merchants, residents and passers-by, with a few tourists as well, and the man at the kerbstone doing acupoint massage, and the dreadlocked kid riding his bike on the sidewalk. This was the spirit of Canal Street, the old jostle and stir unchanged for many decades and bearing no sign of SoHo just above, with its restaurants and artists' lofts, or TriBeCa below, rich in architectural textures. Here were hardware bargains, car stereos, foam rubber and industrial plastics, the tattoo parlour and the pizza parlour.

Then I saw the woman on the prayer rug. I'd just turned the corner, heading south to meet some friends, and there she was, young and slender, in a bright silk headscarf. It was time for sunset prayer and she was kneeling, upper body pitched towards the edge of the rug. She was partly concealed by a couple of vendors' carts and no one seemed much to notice her. I think there was another woman seated on a folding chair near the kerbstone. The figure on the rug faced east, which meant most immediately a storefront just a foot and a half from her tipped head, but more distantly and pertinently towards Mecca, of course, the holiest city of Islam.

Some prayer rugs include a mihrab in their design, an arched element representing the prayer niche in a mosque that indicates the direction of Mecca. The only locational guide the young woman needed was the Manhattan grid.

I looked at her in prayer and it was clearer to me than ever, the daily sweeping taken-for-granted greatness of New York. The city will accommodate every language, ritual, belief and opinion. In the rolls of the dead of September 11, all these vital differences were surrendered to the impact and flash. The bodies themselves are missing in large numbers. For the survivors, more grief. But the dead are their own nation and race, one identity, young or old, devout or unbelieving - a union of souls. During the hadj , the annual pilgrimage to Mecca, the faithful must eliminate every sign of status, income and nationality, the men wearing identical strips of seamless white cloth, the women with covered heads, all recalling in prayer their fellowship with the dead.

Allahu akbar. God is great.

© Don DeLillo 2001. First published in Harper's magazine, December 2001. Don De Lillo's latest novel is The Body Artist, published by Picador, price £13.99.