Heart-breaking messages like "I love you, Daddy" echoed through the site on a warm, cloudless day that was eerily like the morning when terrorists struck the nation.
"We remember the lives lost," Bush said. "We remember the heroic deeds. We remember the compassion, the decency of our fellow citizens on that terrible day."
Elsewhere, cities from Boston to Seattle marked the occasion with solemn speeches, public vigils, memorial dedications and moments of quiet contemplation. Although this year's Sept. 11 observances were generally less elaborate than the first anniversary's, they did not lack for emotion.
"I came here because I wanted to celebrate my sister's life, but it's hard because the wound is still painful," said Michael Smith, a New York carpenter who came to Ground Zero with seven other relatives to hear the name of his sister, Joann Tabeek, read over the loudspeaker system. "I'm trying to keep it together, but after this is over, I'm going to the cemetery, and when that's over I'm going to need a beer."
As he spoke, pairs of children marched to a podium several feet from the pit of Ground Zero, each reading 15 names, which included a parent or other relative. Some blew kisses to loved ones when they read the names. Others choked back tears.
"It wasn't great being up there, but I think it was good for me to do it," a downcast Craig Flickinger confessed. He and his twin 12-year-old brother, Carl, said, "We love you, Dad," after they read 15 names and then left the stage.
Many relatives walked into the concrete pit at Ground Zero, where they left flowers in two reflecting pools representing the twin towers; some also took samples of dust and rock to remember the place where their family members died.
Midway through the nearly three-hour ceremony, Ehtesham Raja consoled six members of his family, who had flown in from Pakistan to commemorate the death of his son Aftab. The 27-year-old computer specialist died in the north tower.
"I never thought in my wildest dreams we would be standing here on a day like this," said the distraught father, hugging his wife and children and gesturing at the crowds. "My son loved New York; he loved America. We thought he was safe here."
The reading of the names was interrupted only by the ringing of four bells marking the moments of each plane's impact and the collapse of the towers. On a day dominated by children's voices and survivors' grief, the handful of officials who spoke confined themselves to quoting great leaders or reading from appropriate poems.
New York Mayor Michael R. Bloomberg, who briefly introduced the ceremonies, read from "The Names" by former U.S. Poet Laureate Billy Collins: "Names of citizens, workers, mothers and fathers. The bright-eyed daughter, the quick son. ... So many names, there is barely room on the walls of the heart."
Later in the evening, officials honored New York victims with the Twin Towers of Light, two beams of light symbolizing the fallen buildings, in a ceremony at Battery Park City.
In Washington, the anniversary was marked across the city with sermons, ceremonies and prayers, even as an 8-foot fence went up around the towering Washington Monument, an example of the fortification that has prevailed since the attacks. As they honored the dead, administration officials spoke of the nation's military conflicts.
At the patched and rebuilt Pentagon, uniformed officers paused to watch television broadcasts of a new videotape purported to be of al-Qaida leader Osama bin Laden and his chief lieutenant. Deputy Defense Secretary Paul D. Wolfowitz told the Fox Network that it sounds as if the tape's editors "were stapling some old news and new news" together "in a pretty crude way."
Even so, the tape altered the focus of the second anniversary from one of remembrance to one of renewed purpose, a senior defense official said.
As he laid a wreath at Arlington National Cemetery, Defense Secretary Donald H. Rumsfeld recalled Bush's vow that the attackers would hear from the United States. Rumsfeld urged support for the administration's war on terrorism, saying, "They did hear from us, and the fight for freedom continues because we know that if we do not fight the terrorists over there in Iraq, in Afghanistan and across the world, then we will have to face them here."
Across the river in the halls of Congress, Republicans also used the day to praise anti-terrorism efforts in Iraq and around the world. Other lawmakers were heavy with gratitude for the passengers who were said to have brought down the fourth hijacked plane in Pennsylvania, which authorities feared was bound for the Capitol.
Bush and his wife, Laura, started the morning at St. John's Episcopal Church across from the White House, where the congregation was asked to pray that God give wisdom and strength to all who govern the nation, "especially George, our president."
After the service, the Bushes observed a moment of silence on the White House lawn, where 2,000 people assembled, from aides in crisp suits to kitchen staff in white chef smocks. The president and his wife continued on to Walter Reed Army Medical Hospital for private visits with 30 wounded soldiers and their families, and Bush awarded 11 Purple Heart medals.
In one of the most moving Washington ceremonies, the children of Leckie Elementary School dedicated a garden to a sixth-grade boy, his teacher and two parents who were killed when American Airlines Flight 77 hit the Pentagon.
Eleven-year-old Bernard Curtis Brown II and his teacher, Hilda Taylor, were on their way to a marine sanctuary in California for an educational field trip sponsored by National Geographic Society. Marsha Ratchford and Johnnie Doctor Jr. worked in the Pentagon and also happened to be parents of children who attended Leckie.
"He wasn't afraid to fly. His thing was, 'Are we going first class?'" Sinita Brown said of her son, Bernard. His teacher had promised to take good care of him on the flight.
"I know she's holding him," Sinita Brown said.
In Boston, more than 400 family members gathered at the Ritz Carlton Hotel for a breakfast in memory of their relatives.
In Seattle, Ely Russell, 42, an engineer, paused in front of a Sept. 11 memorial garden and said: "I think Sept. 11 ought to be a national holiday. All those people lost. And it's funny, you can say those pre-Sept. 11 days were the good old days, and it was only two years ago."
Getlin reported from New York and Fiore from Washington. Los Angeles Times staff writers Shweta Govindarajan, John Hendren, Janet Hook and Elizabeth Shogren in Washington, Elizabeth Mehren in Boston, and researchers Lianne Hart in Houston and Lynn Marshall in Seattle contributed to this report. The Los Angeles Times is a Tribune Publishing newspaper.