As Yo-Yo Ma played the Sarabande to Bach's C minor cello suite, former New York Mayor Rudolph Giuliani began reading the names of the 2,801 husbands and wives, fathers and mothers, sons and daughters, and dear friends lost one year ago in the Twin Towers' collapse.

The roll call of the dead and missing at Ground Zero began after a moment of silence at 8:46 a.m., the time when the first plane struck last Sept. 11, and lasted for more than two and a half hours -- a stark demonstration of the enormity of the disaster.

"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," Mayor Michael Bloomberg said.

Some of the thousands of mourners clutched pictures of the dead and placed roses and personal items around a "circle of honor" at the dusty trade center site, now clear of the twisted metal and other debris that once rose 10 stories high. Some raised American flags. Most bowed their heads in prayer.

Seven-year-old Skyler Mercado clutched the helmet of his firefighter father, Steve Mercado, as wind swirled the dust.

"Gordon M. Aamoth Jr.," Giuliani began. The 32-year-old worked for investment firm Sandler O'Neill & Partners on the South Tower's 104th floor.

Among the 196 readers who followed Giuliani in reading the names were survivors of the attack, New York Sen. Hillary Rodham Clinton, actor Robert De Niro and some of those who lost loved ones, such as Christy Ferer, the widow of Port Authority director Neil Levin.

At 9:03 a.m., the moment the second tower was hit, the ringing of a bell interrupted the recitation.

Marianne Keane, 17, whose stepfather Franco Lalama, an engineer for New York's Port Authority, died in the attack, took the microphone.

"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?"

She added: "I miss you and I hope you didn't hurt too much."

The reading paused again at 9:59 a.m., when the first tower fell. It ended with the sound of taps and the ringing of bells across New York City.

Dignitaries relied on history to express the city's grief -- and its resolve. Gov. George Pataki read from the Gettysburg Address, New Jersey Gov. James McGreevey recited from the Declaration of Independence and, at an evening ceremony, Bloomberg was to recite from Franklin D. Roosevelt's "Four Freedoms" speech.

The day of mourning began in the early hours with drum and bagpipe processions from each of New York's five boroughs to Ground Zero. Hundreds of New Yorkers, many wearing T-shirts that read "I Love New York," joined the procession as it crossed the Brooklyn Bridge.

"I had to be here to say goodbye," said Ellen Stop of Brooklyn.

Officer Jim Coughlan, a bagpiper, described it as a mix of "pride, sadness, mourning and happiness that we're moving on, looking forward to the future, to rebuild."

Across the city, remembrances were planned for nearly every hour of the day -- hospitals honoring fallen paramedics, children's choruses singing mournful tributes, church congregations praying for the lost.

Security was tight at bridges, tunnels, landmarks and the anniversary ceremonies, though officials said there was no specific threat against any target in the city.

The Associated Press contributed to this report.