That morning, Dan Hochman was at work on the 83rd floor of the north tower. He is a trader in the commodities markets. He's also my neighbor. He lives with his wife and children across the hall in our building just below Canal St. In the New York style, we would chat in the elevator, or while picking up the newspapers, or walking together for a few blocks on our various routes downtown. He always left for work early.

The windows in his office on the 83rd floor face north, but that morning, his back was to the windows as he started work on his computer.

He never saw the airplane coming south toward the place where he worked, roaring like a missile over Public School 234, where his children went to school. He had just logged on to the Bloomberg News service.

"Then there was a thump," he remembers. "Not a loud thump, but a big one, and a kind of sound like, like a 'vooomph!'"

The airplane had smashed into the north tower about eight floors above him. He saw no orange flames. "But we knew something big had happened. Then the tower started to sway. Not the way it sometimes creaked in a high wind."

This morning the tower moved in a new way: a rocking kind of sway. "And I thought: We're going over. That was the first thing I thought: Oh my God, we're going over."

This apprehension was enforced by memory.

In 1993, when a massive bomb exploded in the World Trade Center parking garage, Hochman was at the commodities exchange in the WTC complex, where the lights blinked crazily, and some brokers kept working, and smoke drifted into the building, until everyone was in the stairway, where there were no lights, trying to find their way to the street. The terrorists that day had hoped to knock over the tower, and failed.

"That was only eight flights down," he remembers. "But it was a long eight flights. ... This was different."

Black embers

Sept. 11, 2001, was very different. The rocking eased.

"Then everything kind of settled," Hochman remembers. "And we all just stared at each other. Like what was that? Then I looked out the window and saw these black embers floating down in the air. No fireball. Just these black ashes. And I had no clue to what had happened."

The office had a steel door, which meant that Hochman and the others could not see through it. He went to the door and opened it.

"That's when this co-worker, this co-trader, was standing there, and he was burnt," Hochman remembers. He was always wearing a baseball cap, but the cap was gone and so was the man's hair.

"He came at me in a state of shock. He came in and I closed the door behind him. And everybody got wet towels and tried to help him. Then I saw smoke coming underneath the front door."

A few minutes went by, and from thewindows they all saw that things were getting worse. The office was nothot, but the sprinkler caps had allbeen dislodged by the first impact of the airplane.

"We knew we had to get out of there," Hochman remembers. "I remember logging off with a simple message, 'I will not be trading today.'" He laughs. "And from then on there was only one focus: the next step down."

Like most other people, Hochman had one basic mission: "To get the hell out of there."

All the way down, he was thinking of his children, who were students a few blocks away at PS 234.

All the way down, snippets of information were being added by other fleeing workers. They now knew that an airplane had flown into the north tower. "And I had this idea that maybe it had bounced off the building and hit the school."

In the staircase, Hochman saw no panic. "I couldn't get over how calm it was."

Floor after floor to safety

The light was made dimmer by a haze of fine smoke, and when he looked down the stairwell all he could see were hands and arms gripping the banister railing as it descended floor after floor to an unseen bottom.

They had to cross a lobby to a second stairwell. The first 20 flights moved quickly. Then traffic got more clogged as firefighters climbed past them after the 32nd floor, reducing the descent to a single file, "like the Long Island Expressway with one lane closed." Only one man, in a business suit and carrying a briefcase, jumped the line, pushing his way past others.

"By the time I hit the 30s," Hochman remembers, "I thought: I'm down. I got wet on the 12th floor, and then we really were down."

The descent from the 83rd floor had taken about an hour, and when he came out, he discovered for the first time that a second plane had hit the south tower.

He reached the post office at Church and Vesey Sts. when the south tower came down (although he did not see this happen), and that amazing cloud rose into the air.

He ran north, pursued by the cloud, heading for his children's school, which he found covered with powdery ash. At the New York University Law School just south of Washington Square, he found a working telephone and called home. His son answered.

"It's Daddy," Hochman said. "I'll beright home."

All of that was a year ago. The rubble was cleared. Hochman worked in midtown for a while, then moved back to Wall Street. He is home after a summer spent at his family's house on Shelter Island. He did some painting of the house and played with his children and walked around a lot, being human and alive.

He hopes the ruined 16 acres have a variety of future uses, including, of course, a memorial, but also places where trees bloom and children can play.

"Just don't build a target," he says. He thinks no future building should ever be as tall as either of the twin towers, because they will "always be deathtraps." He will not work today.

"I'll just wander around," he says. "I won't avoid the anniversary stuff, but I'm not seeking it, either. I'll probably go to breakfast somewhere, and have the $3 eggs, and just be at peace."