By David Crary ~ The Associated Press

At ground zero, the names took precedence, 2,801 of them read aloud, from Gordon Aamoth Jr. to Igor Zukelman. Patriotic resolve held sway at the Pentagon. And in a field near Shanksville, Pa., grief was partially offset by pride.

At each of the three sites, and in communities across the nation and world Wednesday, Americans and their allies relived the staggering events of one year ago and remembered those who died.

"They were our neighbors, our husbands, our children, our sisters, our brothers and our wives. They were our countrymen and our friends. They were us," New York Mayor Michael Bloomberg told grieving families at the site of the World Trade Center.

New York's roll call of the dead and missing began after a moment of silence at 8:46 a.m. EDT, the time when the first terrorist-piloted plane struck the trade center. It took 2 1/2 hours -- 50 minutes longer than planned -- for 197 readers to complete the list of names.

While wistful cello music accompanied the ground zero ceremony, a booming rendition of the national anthem set the tone for commemorations at the Pentagon, where 184 people died when American Flight 77 smashed into the building.

"Though they died in tragedy, they did not die in vain," declared President Bush, a fist clenched for emphasis. "As long as terrorists and dictators plot against our lives and our liberty, they will be opposed by the United States Army, Navy, Coast Guard, Air Force and Marines!"

After the Pentagon ceremony, Bush flew to southwest Pennsylvania to join commemorations for the 40 people killed when United Flight 93 crashed in a field near Shanksville. The passengers and crew were hailed by Homeland Security Director Tom Ridhe as heroic "citizen-soldiers" for struggling to take back their hijacked plane and avert a possible attack on the Capitol or White House.

"If we learn nothing else from this tragedy, we learn that life is short and there is no time for hate," said Sandy Dahl, the wife of Flight 93 pilot Jason Dahl.

Bush laid a wreath in Shanksville, then another at ground zero after an afternoon flight to New York. He gave no speech, but greeted rescue workers and relatives of Sept. 11 victims.

Far from the sites where the hijacked planes crashed, Americans and well-wishers from other nations found myriad ways to observe the anniversary. In addition to repeated moments of silence, church bells tolled, sirens sounded, musicians performed, and religious leaders groped to find words suitable to the occasion.

"No situation of hurt, no philosophy or religion can ever justify such a grave offense on human life and dignity," Pope John Paul II said at the Vatican. He exhorted the world to heal injustices that cause explosive hatreds.

Among the many places to accommodate memorial services were U.S. military bases in Afghanistan.

"There isn't a place I'd rather be or a job I'd rather be doing," said Lt. Col. Tim Strasburger, an Air Force pilot on duty in Kandahar.

At London's St. Paul's Cathedral, 3,000 white rose petals fluttered down from the dome -- one for each victim who died in the attacks. In Paris, two powerful beams of light were projected into the sky. In Pisa, Italy, a white banner placed by the Leaning Tower read: "From the tower to the towers. Sept. 11, 2002. Memory, solidarity and peace."

At the United Nations, Secretary-General Kofi Annan presided over an international memorial service.

"More than 90 nations lost sons and daughters of their own -- murdered that day, for no other reason than they had chosen to live in this country," he said. "Today, we come together as a world community because we were attacked as a world community."

Many Americans went to work or to school, but it was far from business as usual. Telemarketers cut back on their phone calls, politicians kept their campaign ads off the air, some dealers at a casino in Reno, Nev., even held their cards for a moment in a gesture of respect.

In New Hampshire, trees were planted outside the post offices in the seven towns where Sept. 11 victims had lived. And at E.D. Nixon Elementary School in Montgomery, Ala., sixth-graders baked cookies for local firefighters

Though the government had raised the terror alert to its second highest level, based on new information of possible strikes, no serious incidents were reported. Federal officials told Americans to go ahead with their plans for the day.

In New York City, thousands of mourners gathered at the dusty site of the trade center, clutching pictures of the dead, placing roses and personal items around a "circle of honor." Some waved American flags, many paused to pray.

The first person to take a turn reading the names was Rudolph Giuliani, who as mayor was praised for his steady leadership in the days after Sept. 11. Among those who followed him as readers were survivors of the attack, relatives of those who died, New York Sen. Hillary Rodham Clinton and actor Robert De Niro.

Waiting for the names to be read, Rita Wiley said she was sure that her brother, Daniel Van Laere, died saving people on the 98th floor of the south tower.

"What I'm having trouble getting through is the hour after the plane hit -- what he was thinking, what he was doing," she said, her eyes tearing up.

Marianne Keane, 17, whose stepfather Franco Lalama died in the attack, spoke briefly.

"I would give anything to go back to the morning of Sept. 11 and tell him how much I appreciated everything he's done for me," she said. "But I think he knows that now. In my eyes, he died a hero. And how much more could you ask for?"

As the ceremony proceeded, a camouflaged military helicopter with a protruding gun turret circled overhead, while snipers and tactical units kept watch.