Though not all New Yorkers are taking part in the day's ceremonies, they all remember.
It's been 365 days since two planes pierced the city's most visible landmarks and turned them into ash and rubble. And no one, from grammar-school children downtown to African immigrants in Harlem, could look up at the day's beautiful blue skies today without recalling the tragedy.
Early in the morning on the first anniversary of Sept. 11, Pauline Duke, 32, was a block north of the site before the day's ceremonies were to begin, speaking with police officer friends. But she didn't look like she wanted to be there.
Duke said she was still suffering from the attacks. The East Northport, N.Y., supermarket clerk said she could still feel the fear she knew when her father, a New York City police officer, was unable to get in touch with her for three long days after the attacks.
"There's still a lot of pain in my life because of that," she said as she made her way away from the site. "It still hurts, and my father still lives through it every day."
Also trying to escape from the World Trade Center memorial events was Armando Nunez. On the No. 5 subway train, the 63-year-old recounted his experience as a window washer at a tall building near the World Trade Center that day.
"When they attacked, it sounded like a big bomb exploded," he said, gesturing with his arms as other passengers listened, rapt. "I was so scared. We went into the building and started helping people, giving them bottles of water, wiping the asbestos from their faces."
He said he'll never forget the horrors he witnessed that day.
"This man came running over and jumped into the fountain and bled to death," he said. "People were trampling on top of other people. I saw everything."
Nunez washed windows at his building the morning of the anniversary, but steered clear of the ceremonies.
"I didn't want to get too close. Bad memories," he said before transferring to a train that would take him home to Brooklyn. "Every time I'm working and we hear the airplanes, we hear them coming and we all look up and think it could be happening again."
Farther away from the site, the emotions seemed to run less hot.
At St. Patrick's Old Cathedral, 10-year-old Christopher Delarosa held a flag and acted as a miniature honor guardsman as his classmates marched by, part of a school commemoration. He said marking the anniversary comforted him.
"I feel better because we're doing all this stuff for the people that died," he said.
In the East Village, bellydance instructor Sandra Catena, 44, said her biggest thought was how anxious she was about travelling to New Jersey later that day.
"I feel very surreal," she said. "I'm worried about going through the tunnels. It's the feeling of lead in the belly."
Nearby, at Tompkins Square Park, where hipsters butt up against yuppies, magazine photographer Nick Cardillicchio, 35, said he would mark the day by going for a motorcycle ride.
"I decided that morning a year ago that my only job was to survive, because I didn't know what was going to happen," he said, wiping off a BMW bike. "And I've decided today that I've survived and I'm not going to be sad anymore. So I'm going to go take a ride all around the city, just like I did last year."
Far to the north of the World Trade Center, in Harlem, the daily bustle looked like it does most days on 125th Street, with men and women shopping, children pleading for toys and vendors hawking CDs, shoes, jewelry, snacks. But Sept. 11 was still on everyone's minds.
In front of the hair salon where they worked, Fanta Kave, 35, her sister Fatoumata Kane, 28, and Sally Forfana, 33, all immigrants from the Ivory Coast, enjoyed the warm sun between appointments. But glancing south, they admitted they're still worried.
"We all feel sad," Kave said, translating her friends' comments from their native tongue. "We're not watching TV today. Business has gone down and everything has become very hard since Sept. 11. We don't even know if we feel safe or not."
In front of the Apollo Theater, 20-year-old college student Juan Williams, 26-year-old medical assistant Denise Cartagena and Cartagena's 2-year-old daughter, Mia Washington, were out taking a leisurely walk before going down to see the World Trade Center site.
"I had to get out of the house," Cartagena said. "I couldn't watch it on TV anymore. I'm taking it easy, happy to be with my family. But I'm scared every day, when I ride the bus, when I ride the train, when I enter big buildings. Even when I breathe."
Back in downtown, Manhattan workmen were installing the last bits for the stalls for the annual San Gennaro festival in Little Italy. Riding through it all was filmmaker King Molapo, who said he was making a point of doing nothing different this day. Molapo contributed to Seven Days in September, a documentary about the attacks.
"What else should I do? I'm doing nothing today," the 36-year-old said. "I'd be lying to say it is like every other day -- it's Sept. 11. I don't think people are going to forget about what happened -- 3,000 people died that morning, and you can't forget that. But what can I do besides be careful and try to be aware of how your day goes? That's all I can say."
And then, with a smile and a wave, Molapo hopped on his bike and rode away.