From the vibrant heart of Lower Manhattan to a quiet meadow in Pennsylvania, family members, police officers, firefighters, presidents and many other Americans marked the 10th anniversary of the Sept. 11 attacks with ceremonies that reflected the losses of that day, but that gave the world its first glimpses of the monuments built to keep the victims' memories alive.

The sky over New York City was clear and blue, as it was a decade earlier when terrorists hijacked four jets that crashed into the World Trade Center, the Pentagon and a field near Shanksville, Pa. A light breeze hinted at the arrival of fall. As the sun rose over Manhattan, a crowd gathered inside the former World Trade Center site. Bagpipers, keeping step with the mournful pounding of a drum, took their places on the National September 11 Memorial plaza, which opens to the public Monday.

As in past years, relatives took turns reading the names of each person killed that day in alphabetical order, from Gordon M. Aamoth Jr. to Igor Zukelman, and the six people killed in the 1993 bombing of the World Trade Center. The youngest was 2, Christine Lee Hanson, who was on United Airlines flight 175. The oldest was 85, a passenger named Robert Grant Norton on American Airlines Flight 11.

There were 2,983 names in all, recited by survivors who sent personal messages to their mothers, fathers, brothers, sisters, spouses and children as they took turns at the microphones. "We miss … your meatloaf," said one. "Daddy, I miss you," said a little girl in shiny red shoes, who needed a step to reach the microphone.

They spoke with accents from all regions of the globe. Children announced births of their own children to the grandparents they would never meet. Teenagers told their dead parents of college and career choices, and of their halting moves into adulthood. "Dad, I'm still learning to cook but I'm working on it," said one.

President Obama, former President George W. Bush and mayors and governors past and present were among those at the main ceremony in New York, but they spoke briefly, if at all, in keeping with Mayor Michael R. Bloomberg's vow to make this event one for the families, free from politics.

The events were in marked contrast to last year, when thousands of fist-waving activists held rowdy protests either for or against the planned opening of a mosque and Islamic center near the World Trade Center site, which then resembled a chaotic construction zone rather than a place of contemplation.

The Islamic center has yet to be built, and the construction cranes remain active as work continues on the skyscrapers, museum and transportation hub that will share space eventually with the memorial.

But on this day, neither heavy machinery nor political oratory competed with the sounds of sadness.

"Ten years have passed since a perfect blue-sky morning turned into the blackest of nights," Bloomberg said. "Although we can never un-see what happened here, we can also see that children who lost their parents have grown into young adults, grandchildren have been born, and good works … have taken root."

With that, at exactly 8:46 a.m., he proclaimed a moment of silence to mark the moment of first impact: the crash of Flight 11 into the north tower. Only the rushing of water pouring into reflecting pools where the north and south towers once stood broke the quiet. The pools and waterfalls are the centerpieces of the Sept. 11 memorial, which was completed weeks before the ceremony. The moment of silence was repeated five more times to mark the crashes of the three other planes and the collapse of each tower.

Once the recitation of names began, relatives were given their first chance to see the memorial up close and to touch the bronze parapets ringing the reflecting pools and etched with victims' names. Many used crayons and pieces of paper to make stencils of the names. Others laid flowers or left notes or photographs. Many stood quietly, while others sobbed openly.

All ran their fingers over and over the letters, as if to touch their lost relatives one more time.

"When you have a loved one who died, you either have a gravestone or you don't. We don't, so this is his burial ground," said Tom Acquaviva, whose son, Paul, died at the World Trade Center.

"I think it's absolutely beautiful," said his wife, Jo, who took comfort in knowing that she now has a place to visit her son, who was 29 when he died.

It was the first time Cheryl Shames had brought her 12-year-old daughter and 7-year-old twins to the ceremony, to remember her 27-year-old brother, Andrew Steven Zucker. "They're finally old enough to deal with such a long, emotional day," she said, displaying the page of the memorial program on which her children had etched their uncle's name, using a purple crayon.

Shames was among the family members who objected to the design of the memorial, which was chosen in 2004 from among 5,201 proposals by a jury that included architects, politicians and victims' relatives. The designer, architect Michael Arad, called it "Reflecting Absence," and said the endless streaming of water into two vast pools where the towers once stood represented the futility of filling the voids left by those killed. More than 400 oak trees represent regeneration of life.

"It's so peaceful," said Shames' daughter, Temima. "I heard birds."

Shames, though, had hoped the entire 16-acre site where the World Trade Center complex stood would be devoted to a memorial. Instead, office buildings will occupy about half the ground.