Relatives of victims killed at the World Trade Center gathered at ground zero in lower Manhattan for readings from dignitaries and a recitation of the names of the dead. Presidential candidates Barack Obama and John McCain visited the site to pay silent respects. In all, almost 3,000 people from over 90 countries were killed in the separate attacks on three sites in the United States.
"Today marks the seventh anniversary of the day our world was broken," Mayor Michael Bloomberg said at the start of the ceremony, calling September 11, 2001, a "day that began like any other and ended as none ever has."
The ritual at ground zero included moments of silence at 8:46 a.m., 9:03 a.m. and 9:59 a.m. and 10:29 a.m. - the times when two hijacked jets slammed into the trade center buildings and the twin towers fell.
Later, McCain and Obama walked together into the great pit where the World Trade Center once stood. The two rivals stopped to talk with a small group of family members of the attacks' victims of seven years ago. They laid flowers at the pit's commemorative reflecting pool, bowed their heads and walked off to speak with fire and police personnel. There were no speeches.
Services were also held in Pennsylvania and at the Pentagon, where a new memorial was dedicated.
The attacks, claimed by al-Qaida, paved the way for President George W. Bush - then less than a year into his first term - to launch an attack against Afghanistan, where the terror group's leader Osama bin Laden was hiding. They also served as justification for the attack on Iraq, which led to the toppling of Saddam Hussein's regime.
Among the speakers at ground zero were three children who were very young when their father went to work at the World Trade Center seven years ago and never came home.
"I remember playing in the yard with him. I remember him pulling my wagon. He was strong. He always made me feel safe," said Alex Salamone, wearing the football jersey of his father, John. "I wish I could remember more, but we were so young when he died."
Edward Bracken, who lost his sister, Lucy A. Fishman, said she was "murdered by coward men using their religion to say they are right and we are wrong," then added, "Pray for the men and women who sleep on the ground every night in the Middle East to keep our world safe."
In Washington, Bush led a White House gathering in observing the moment which served to shape his presidency. Standing next to him under threatening skies for the brief South Lawn ceremony were his wife, Laura, and Vice President Dick Cheney and his wife, Lynne.
The assembled crowd in Washington numbered in the hundreds and included leaders of Congress, members of the Cabinet, diplomats, men and women in military uniform and others who work at the White House. Across the Potomac River, a new memorial at the Pentagon was dedicated as the names of the victims were read aloud to mourners there.
Bush also helped dedicate that memorial. He said the terrorists could not break the resolve of the U.S. armed forces who have "taken the fight to the terrorists abroad so we do not have to face them here at home."
"Thanks to the brave men and women, and all those who work to keep us safe, there has not been another attack on our soil in 2,557 days," he said.
The Pentagon Memorial, built at a cost of $22 million, contains 184 benches that will glow with light in the night, as well as trees and trickling water. Each bench is dedicated to an individual victim, and the structures are organized as a timeline of the victims' ages, moving from the youngest, 3-year-old Dana Falkenberg to the oldest, John D. Yamnicky, 71. Nearly 3,000 flags are arrayed in a Pentagon parking lot.
Bush called it a place of learning for future generations.
"The day will come when most Americans have no living memory of the events of September the 11th. When they visit this memorial, they will learn that the 21st century began with a great struggle between the forces of freedom and the forces of terror," he said. "They will learn that this generation of Americans met its duty: We did not tire, we did not falter, and we did not fail."
His comment recalled his promise to Americans on Oct. 7, 2001, when the United States launched its strike against al-Qaida and the Taliban in Afghanistan. Bush said at the time: "The battle is now joined on many fronts. We will not waver; we will not tire; we will not falter; and we will not fail."
Said Defense Secretary Robert Gates: "This memorial tells the story to future generations. They won't directly feel the heat, smell the smoke or know the horror of that day, but they will know, as the inscription says, that we claim this ground."
Relatives of victims began arriving at dawn Thursday at New York's ground zero, now a huge construction site. American flags were draped over silent cranes.
Relatives of victims began arriving at dawn at ground zero, now a huge construction site. American flags were draped over silent cranes, and some families held signs saying "We miss you," ''We love you" or "You will never be forgotten."
Family members and students representing more than 90 countries that lost victims on that day read the names of 2,751 people killed in New York, one more than last year. The city restored Sneha Philip, a woman who mysteriously vanished on Sept. 10, 2001, to its official death toll this year after a court ruled that she was likely killed at the trade center.
McCain and Obama planned to visit the site after the ceremony concluded Thursday afternoon. The candidates agreed weeks ago to pull their campaign ads for the day and were appearing together Thursday night at a forum on volunteerism and service.
Obama called on Americans to renew "that spirit of service and that sense of common purpose" that followed the terrorist assaults that killed nearly 3,000 people. McCain, in Shanksville, Pennsylvania, asked every person "to be as good an American" as the passengers and crew of United Airlines Flight 93 after they rose up against the hijackers.
Former Mayor Rudy Giuliani was to speak at the ceremony in New York, as he has every year in New York, along with officials including Bloomberg and Homeland Security Secretary Michael Chertoff.
Last year's reading by Giuliani, then a Republican presidential candidate, drew protests from family members who said the city was ill-prepared for the terrorist attacks under his leadership and questioned whether he should be there while running for the White House.
Many families had no opposition to McCain and Obama's visit, but some questioned whether the visit was necessary. "It's probably going to be more commercial. This really should be a day for the people who lived and worked down here," said Jane Wixted, who lost her police officer son Glen Pettit on Sept. 11.
But Pettit's former colleague, Chris DeAngelo, was glad they were coming. "One of them is going to lead this nation," he said. "And for that reason, both should come here to see what happened."
In Pennsylvania, several hundred people gathered to read the names of 40 victims killed in Shanksville where Flight 93 came down after passengers reportedly stormed the cockpit to thwart terrorists' plans to use that plane as a weapon like the others.
Memorials are years away from being built in Pennsylvania and New York. As in past years, two bright blue beams of light will shine at night on the New York City skyline, in memory of the fallen towers.
