In New York, Washington and Pennsylvania, across the United States and the world, people carried out rituals now as familiar as they are heartbreaking: American flags unfurled at the new World Trade Center tower and the Eiffel Tower, and tears shed at the base of the Pentagon and a base in Iraq.
President Barack Obama quoted the Bible and spoke of finding strength in fear. George W. Bush, still new to the presidency that day, invoked the national sacrifice of the Civil War. Vice President Joe Biden said hope must grow from tragedy.
And Jessica Rhodes talked about her niece, Kathryn L. LaBorie, the lead flight attendant on the plane that hit the south tower. She remembered a radiant smile and infinite compassion, and suggested that now, 10 years on, it is time to turn a corner.
"Although she may not ever be found, she will never ever be lost to her family and her friends," Rhodes said after she read a segment of the list of the dead at ground zero. "Today we honor her by letting go of the sadness over losing her and embracing the joy of having known her."
It was the 10th time the nation has paused to remember a defining day. In doing so, it closed a decade that produced two wars, deep changes in national security, shifts in everyday life - and, months before it ended, the death at American hands of the elusive terrorist who masterminded the attack.
"These past 10 years tell a story of resilience," Obama said at a memorial concert at the Kennedy Center after he visited all three attack sites.
"It will be said of us that we kept that faith; that we took a painful blow, and emerged stronger," he said.
The anniversary took place under heightened security. In New York and Washington especially, authorities were on alert. Ahead of the anniversary, the federal government warned those cities of a tip about a possible car-bomb plot. Police searched trucks in New York, and streets near the trade center were blocked. To walk within blocks of the site, people had to go through checkpoints.
The names of the fallen - 2,983 of them, including all the victims from the three Sept. 11 attack sites and six people who died when terrorists set off a truck bomb under the towers in 1993 - echoed across a place utterly transformed.
In the exact footprints of the two towers was a stately memorial, two great, weeping waterfalls, unveiled for the first time and, at least on the first day, open only to the relatives of the victims. Around the square perimeter of each were bronze parapets, etched with names.
Some of the relatives were dressed in funereal suits and others in fire department T-shirts. They traced the names with pencils and paper, and some left pictures or flowers, fitting the stems into the recessed lettering.
At the south tower pool, an acre in area and 30 feet deep, Mary Dwyer, of Brooklyn, remembered her sister, Lucy Fishman, who worked for Aon Corp., an insurance company that occupied seven floors near the very top.
"It's the closest I'll ever get to her again," she said.
One Sept. 11 relative pronounced the memorial breathtaking. An underground section and a museum won't open until next year, but for many of the families, the names were enough.
"It breaks me up," said David Martinez, who watched the attacks happen from his office in Manhattan, and later learned that he had lost a cousin and a brother, one in each tower.
At memorial services, people talked of grief and loss and war and justice. But they also talked of moving forward.
"Every year it becomes more significant," Barbara Gorman said at a service for the Port Authority dead, which included 37 police officers, one of them her husband, Thomas. "My kids are 25, 21, 18. They understand now. It's not so much a tragedy anymore as history, the history of our country."
In the decade between then and now, children have grown. The second-graders who were with Bush on the morning of Sept. 11, 2001, will graduate high school next spring. And children who were in the cradle or the womb on that day are old enough to read names at the anniversary, old enough to bear the full burden of their grief.
"You will always be my hero," Patricia Smith, 12, said of her mother.
Nicholas Gorki remembered his father, "who I never met because I was in my mother's belly. I love you, Father. You gave me the gift of life, and I wish you could be here to enjoy it with me."
Alex Zangrilli said: "Dad, I wish you were here with me to give me advice, to be on the sidelines when I play sports like all the other dads. ... I wish we had more time together."
Madeline Hoffman smiled as she said to her father: "Everyone always tells me I look and act just like you." And Caitlin Roy, whose father was a firefighter, said: "I want to thank you for the nine years you spent as my dad. They were short but not without their benefits. We're taken care of now. We're happy."
Obama, standing behind bulletproof glass and in front of the white oak trees of the memorial, read a Bible passage after a moment of silence at 8:46 a.m., when the first jetliner slammed into the north tower 10 years ago.
The president, quoting Psalm 46, invoked the presence of God as an inspiration to endure: "Therefore, we will not fear, even though the earth be removed, and though the mountains be carried into the midst of the sea."
Obama and Bush, joined by their wives, walked up to one of the pools and put their hands to some of the names. Bush later read from a letter that President Abraham Lincoln wrote to a mother believed to have lost five sons in the Civil War: "I pray that our heavenly father may assuage the anguish of your bereavement."
In a ceremony at the Pentagon, Biden paid tribute to "the 9/11 generation of warriors."
"Never before in our history has America asked so much over such a sustained period of an all-volunteer force," he said. "So I can say without fear of contradiction or being accused of exaggeration, the 9/11 generation ranks among the greatest our nation has ever produced, and it was born - it was born - it was born right here on 9/11."
Defense Secretary Leon Panetta paid tribute to 6,200 members of the U.S. military who have died in the Iraq and Afghan wars. One hundred eighty-four people died at the Pentagon.
In Shanksville, Pa., a choir sang at the Flight 93 National Memorial, and a crowd of 5,000 listened to a reading of the names of 40 passengers and crew killed aboard the fourth jetliner hijacked that day a decade ago. Obama and his wife traveled to the Pennsylvania town after their visit to New York and placed a wreath at the memorial.
During the president's visit, members of the crowd chanted, "USA! USA!" One man called out: "Thanks for getting bin Laden!" It was the first anniversary observance since al-Qaida leader Osama bin Laden was killed by U.S. forces in Pakistan in May.
In a brief scare, two military aircraft escorted a New York-bound American Airlines flight from Los Angeles. Three passengers made repeated trips to the bathroom and some people thought they were using hand signals to communicate, but the men were cleared and sent on their way, said a law enforcement official who was not authorized to speak publicly and spoke on condition of anonymity. The official said earlier reports that the men had locked themselves in the bathroom were incorrect.
Fighter jets also shadowed a Denver-to-Detroit Frontier Airlines flight after the crew reported that two people were spending an unusual amount of time in the bathroom. The FBI said a search of the plane turned up nothing and three passengers were questioned and released.
"Due to the anniversary of Sept. 11, all precautions were taken, and any slight inconsistency was taken seriously," said Sandra Berchtold, an FBI spokeswoman in Detroit.
For the most part, in New York, away from the trade center, it was a pleasant September Sunday. People had brunch outdoors. Bicycles crowded the paths along the Hudson River. Families strolled around. Sailboats caught a river breeze and drifted past the dock where emergency vessels evacuated trade center survivors.
Elsewhere in the nation, it was a day not to bring life to a stop, as it was 10 years ago, but to pause and reflect.
Outside FedEx Field in Landover, Md., fans got ready for the first Sunday of the NFL season, the Redskins and Giants, Washington and New York. There was extra security at the stadium. Scott Millar, a Redskins season ticket-holder, used the logic of post-Sept. 11 America in deciding to go to the game.
"You've got to trust the security. You've got to trust the people who are here to protect you," he said. "We're here to have a good time."
In southwest Missouri, where 160 people died in May in the nation's deadliest tornado in six decades, New York firefighters and ground zero construction workers joined survivors in a tribute to the victims of Sept. 11.
The New York contingent brought a 20-by-30-foot American flag recovered a decade ago from a building near the trade center. Survivors of a Greensburg, Kan., tornado began repairing the flag in 2008, using remnants of flags from their town. The final stitches are being made in Joplin, Mo., and then the flag will go to the National 9/11 Memorial Museum. Missouri is the last stop on a 50-state tour to promote national unity and volunteerism.
"We're so far away from the World Trade Center," said Christy Miller, who brought her mother and two children to the Joplin tribute. "But it doesn't matter how far away you are."
Some observed the day as a time to serve. Thousands cleaned parks, renovated community centers and gave blood as they did in the days after the 2001 attacks. Some said they were trying to reclaim good will that they said has been lost amid political rancor and economic fear.
"As unfortunate as it was, it seemed like it put us all back into the frame of mind that life wasn't just about me," said Yvette Windham, who joined 200 people to build seven new homes in a Nashville, Tenn., neighborhood.
The world offered gestures large and small. The Colosseum in Rome, rarely lit up, glowed in solidarity. Pope Benedict XVI encouraged people to resist "temptation toward hatred" and focus on justice and peace. Taps sounded in Belgium and in Bagram, Afghanistan. In Madrid, they planted 10 American oak trees in a park, led by a prince.
And in Malaysia, Pathmawathy Navaratnam woke up Sunday in her suburban Kuala Lumpur home and did what she's done every day for the past decade - say "good morning" to her son, Vijayashanker Paramsothy, who was killed in New York on Sept. 11, 2001.
"He is my sunshine. He has lived life to the fullest, but I can't accept that he is not here anymore," Navaratnam said. "I am still living, but I am dead inside."
The Taliban marked the anniversary by vowing to keep fighting against U.S. forces in Afghanistan, insisting that they had no role in the Sept. 11 attacks. They railed against "American colonialism" and said Afghans have "endless stamina" for war.
Hours later, a Taliban suicide bomber blew up a large truck at the gate of a Combat Outpost Sayed Abad in Afghanistan's eastern Wardak province, killing two civilians and injuring 77 U.S. troops.
"Some back home have asked why we are still here," U.S. Ambassador Ryan Crocker said at a 9/11 memorial at the embassy in Kabul. "It's been a long fight and people are tired."
"We're here," he said, "so that there is never again another 9/11 coming from Afghan soil."
Associated Press writers Verena Dobnik, Jim Fitzgerald and Tom Hays in New York; Tamara Lush in Nashville, Tenn.; Ben Feller and Nancy Benac in Washington; Joe Mandak in Shanksville, Pa.; Jamey Keaten in Paris contributed to this report.