For the past 27 years, Brian Clark has gone daily to his office at the World Trade Center. Never again.

"It is going to be strange," said the 54-year-old Toronto native and executive vice-president of Euro Brokers, an international brokerage firm whose offices occupied the 84th floor of the South Tower. "I don't know what to expect."

Three days after the horrifying terrorist assault on New York's financial district, Clark related an emotional tale, a miraculous mixture of instinct and fate and luck that guided him 84 floors to safety during the attack. Fifty-nine of his 275 colleagues are missing.

He spoke yesterday from his home in Mahwah, N.J., where he has lived with his wife Dianne, his Thornhill, Ont., high-school sweetheart, since Euro Brokers relocated from Toronto in 1974. The couple have four children, two still at home.

When he arrived home after airplane attacks that left the World Trade Center and much of the financial district a smoldering ruins, he drove into the driveway honking the horn. Dianne and daughter Kristen and son Tim, neighbours and friends, raced across the lawn to welcome him.

That's when he cried.

"Yeah, I did then. And I am now."

Several hours had passed since he had gone to the office that morning, but Clark had no sense of what had really taken place, that the world had changed, that it would never be the same.

"While everything was happening, time was suspended. I was in a bit of a bubble. I knew nothing about the Pentagon or the hijacked planes. I knew I was fine. I'm an optimistic person. I had a faith in me and I proceeded that way."

Clark had been at his desk about an hour when the first plane, American Airlines Flight 11, slammed into the neighbouring North Tower.

Some of his colleagues left their desks and started down the stairs. But many did not, thinking it was a light aircraft accident, an isolated incident.

"The first plane's impact was a wonderment, initially," he said. "I called my wife to say a plane hit the World Trade Center but not to worry because it's the other tower. Shortly after that, an announcement came over the public address system that our building was secure and for workers to return to their desks. It turned out to be wrong.

"We watched Tower One burning for 15 minutes. My colleagues saw people jumping out windows. I didn't. I couldn't. One woman in tears screamed, 'Brian, people are dying.' She ran to me. I encircled her with my arms. She went into the ladies room to compose herself. That was 10 minutes before the plane hit us. I didn't see her again. She'd probably gone back to her desk."

There were about 60 of Clark's co-workers on the floor when United Airlines Flight 175 slammed into their building, five to 10 floors below their office. Clark was huddled with a half-dozen people.

"Instant destruction. It was as if the building rocked and swayed. It might have only been a matter of feet, but it felt like yards. The ceilings collapsed. Speakers, lighting fell. Doorways popped out of walls. Drywall shredded. Floors popped up. Our group just knew right away: terrorism. Before, with the first plane, you didn't know. We knew then.

"We took off down the hallway, into the centre core, to stairway A. But we'd only gone a few floors when we encountered a heavy-set woman laboriously coming up the stairs with a more frail man. We said we were going down. They said they'd just come from a floor in flames."

The group going down began to argue with the couple going up. They were on the 81st floor.

"It became quite an argument there on the stairs. There was debris and it was dusty, but it was mostly construction dust. You could start to smell the fire. I said we had to get below the flames. The lady was arguing with me. In the back of my mind. I just had this instinct that down was better than up.

"Then I heard someone banging on the wall, saying, 'Help me, help me. I can't breathe. I can't get out.' "

As Clark moved toward the voice, the others decided to return to their office, above the fire where they hoped helicopters would rescue them and sprinklers would douse the blaze.

Only one other member of the group, fellow Canadian Ron DiFrancesco from Stoney Creek, Ont., would descend the 81 floors. As the others were climbing to their inevitable deaths, Clark discovered a hole in the wall. He squeezed through it to find the source of the voice: Stanley Praimnatch, a Fuji Bank employee from Elmont, N.Y.

"I have this image of four of my workmates turning around and helping this woman and saying, 'We can do it. We'll be fine,' " Clark said. "I have this image of heroes making a very bad decision.

"The beams were melting and the building was coming in."

DiFrancesco, meanwhile, felt overcome by smoke and fumes, and started down the stairs while Clark was helping Praimnatch from under some rubble. Clark would not learn of his whereabouts until hours later, when DiFrancesco turned up at St. Vincent's Hospital, suffering from a head wound.

"The fumes weren't slowing me down," Clark said. "After I wrestled with what Stanley was buried under, he gave me this big hug. We started down the stairwell, and amazingly, there was no one there. We headed down.

"Finally, we got to a lit stairway with clean air about the 70th floor. From 81 to 70, we were going over shrapnel, drywall and debris. It wasn't easy, but we were working hard to get out of the building. When we got to the 70th floor, the lights were on and I saw Jose Marrero, a fellow who works with me. He had a walkie-talkie and he was going up. I said, 'Don't go up.' But he kept walking up, saying he had to help the others. Again, I saw a hero making a bad decision. And I didn't know where Ron was, but I was hoping he'd just gone down."

When they arrived at the 44th floor, a sky lobby, they found a security guard tending to a man with severe head injuries. The guard asked them to find help. They continued to the 31st floor.

"We found a conference room. The phones were working. I called my wife and said we were close to getting out. It was about 20 minutes to 10 o'clock. It was 35 minutes after the plane had hit. So the anguish back home was enormous. Stanley called his daughter. Then I called EMS to tell them about the injured man. At that point, the sense of urgency was muted. I was actually on hold with EMS for about four minutes, which now seems unreal. We actually felt quite safe, with no concept that the building would collapse."

After making three phone calls, the pair continued their descent. They encountered no obstacles and quickly covered the last 30 floors, finally emerging inside the concourse at street level.

"Suddenly, we were looking at the plaza and it looked like a moonscape. Usually, there is a fountain and flowers and people. But it was just debris everywhere. Parts of the plane were there. Pieces of wall. It looked like it had been deserted for a hundred years. We saw a policeman, who calmly told us to go to Victoria's Secret, then turn to Sam Goody and out onto Liberty Street. We got outside, and thought we'd made it. Then a cop said if we were going to cross the street, we'd better run for it, because there was debris falling everywhere. Nobody was around. There's normally so many people. It was eerie. It was surreal.

"We headed down the street, south a few blocks to Trinity Church. Stan said, 'Let's go into this church.' But first we stopped and turned to look at the World Trade Center and Stan said that the tower could come down. I said, 'No way. It's a steel structure. There's no way.' I finished that sentence and the tower plummeted. Our jaws dropped. Then the plume rose. Everybody ran. The dust engulfed everything. We ran. I ended up at the Fulton Ferry Terminal. I couldn't believe my luck. A fellow was announcing the next ferry was for Jersey City, and that's where I was going. Not a long time after that, we were again engulfed by a big cloud of black dust, the result of Tower One falling down."

Clark boarded the ferry. It sailed around the southern end of Manhattan. Passengers were speechless, staring in shock and awe at the changed landscape.

"For 27 years, I've worked at the World Trade Center and suddenly it wasn't there any more," he said. "You could see the collateral damage and you just knew the devastation was far beyond imagining. I wasn't sure what the future was."

The ferry docked and he called his wife. He walked a mile to the Hoboken train station.

"Again I was lucky. There was a train waiting. And I went home."

It wasn't until hours later, and even the following day, that the magnitude of the trauma began to sink in.

Praimnatch, the man Clark had rescued on the 81st floor, phoned at midnight to say he had been at the hospital, pretty scraped up, but alive.

"He said, 'You saved my life.' But I think he may have saved mine. When I stopped to help him, the others went up and I stayed. It was my instinct to go down, but stopping to help him . . . you never know. We will be lifelong friends, for sure.

"All these things happen for a reason. I've had to talk to the wives whose husbands went back up the stairs. I've had to tell that story many times. They're concerned and worried. They're not grieving quite yet. But I think it may be starting to sink in. You have to be realistic. At the same time, we're going to try and recreate a business. We still have offices in London and Toyko. We still have a lot of good employees. The focus has to be on healing a bunch of wounds of people we love. It is hard. It is. But you have to be optimistic."

Clark won't take his telephone off the hook. He allows it to ring almost endlessly, though he likely needs sleep and serenity and the comfort of his family more than anything. He holds out hope that some of his missing colleagues will turn up, even as he watches the horror unfold on television, again and again.

Not surprising, one image haunts more than others -- the second plane slicing into his building.

"It's something I can't get rid of," Clark said. "It wasn't until the next day that I saw it. And the strange thing is that I experienced it, but I didn't see it. To see it now, and know that plane is hitting six floors below mine.

"I haven't reached the anger stage yet. Apparently, I have yet to go through that. I guess that will happen. I'm not normally an angry person. Maybe I won't be. I don't know. At the moment, I'm more in sorrow and sympathy.

"It's had an effect on me. My emotions are different today than they were the day before. Today, a lot more emotions set in on me. I don't know what good will come of this. I'm aware of the ramifications of retribution. And that there is some evil that needs to be stopped.

"But vengeance is the Lord's work. Not mine."