Friends and family members leave flags and flowers at the National 9/11 Memorial on Sept. 11, 2012.
Photo credit: Fire Department City of New York
Fire Commissioner Salvatore Cassano is seen at the Fireman's Monument on Manhattan's Upper West Side on Sept. 11, 2012.
Photo credit: Fire Department City of New York
Eleven years after the shocking 9/11 terrorist attacks, Americans mourned those who were lost, holding vigils, attending religious ceremonies, volunteering for community service and posting Facebook remembrances.
"It is extremely important that people never forget what happened on Sept. 11," New York City Fire Commissioner Salvatore Cassano said.
Tuesday morning, members of victims' families and others gathered at Ground Zero, the Pentagon and near Shanksville, Pa., to honor the nearly 3,000 people who were killed at those spots.
At the National September 11 Memorial plaza -- an area that once held the twin towers but now hosts two memorial pools -- family members recited the names of those who perished there. They also read the names of those killed at the Pentagon, on Flight 93 and in the 1993 World Trade Center bombing. Several in the crowd held up photos of loved ones.
The Pentagon ceremony was held at the National 9/11 Pentagon Memorial, where 184 metal benches memorialize the 59 crewmembers and passengers and 125 people who were killed there.
President Obama spoke at that commemoration.
"No matter how many years pass, no matter how many times we come together on this hallowed ground, know this: that you will never be alone," Obama said. "Your loved ones will never be forgotten."
In Shanksville, the ceremony at the Flight 93 Memorial included Vice President Biden, servicemembers and others wearing red, white and blue. They honored the passengers killed while fighting terrorists for control of the hijacked plane.
"What they did for the country is still etched in the minds of not only you, but millions of Americans," Biden said. Relatives and community members read the 40 names of the Flight 93 passengers and crew and rang bells of remembrance.
Patrick White, president of Families of Flight 93, said the permanent memorial allows people to feel a closer connection to those killed in that crash.
"Being able to put your hand on the gleaming white walls and touch the names of the one that we lost is something that is just very real and tangible," said White, whose cousin Louis J. Nacke II died when Flight 93 plunged into a field.
Along with the official speeches and ceremonial processions, there were many less formal remembrances Tuesday. Some people went to religious services or had private moments of quiet reflection. Others did volunteer work on their own or joined an organized effort.
Financial services firm Cantor Fitzgerald & Co., with its affiliate BGC Partners, held its annual charity day. The global firm's revenue from Tuesday, approximately $12 million, will be donated to more than 100 charities and be used to help those affected by the 9/11 attacks.
Cantor Fitzgerald, which occupied offices in the north tower, had 658 employees perish that day.
The New York City Fire Department -- which lost 343 members -- had remembrances of its own.
Early on Tuesday, Ladder 35 and Engine 40 in Manhattan were setting up their annual breakfast for active and retired members, as well as family members of those who died. "We lost 11 that day -- everyone who was working," Ladder 35 Capt. John Miles said.
He said even as the years pass, most of the families still come to the breakfast, which includes moments of silence and honoring the firefighters who died.
"It's good for us that they (the family members) are here, and it's good for them that we are here," Miles said.
Many still looked forward.
"This anniversary allows us to renew our faith that even the darkest night gives way to a brighter dawn," Obama said.
Some readers at the World Trade Center spoke directly to deceased loved ones, telling them of the accomplishments their children had made in the past 11 years.
Social media users posted messages of love and peace. Some urged moving on rather than replaying the day.
Brian Jordan, a Roman Catholic priest who ministered to responders, construction workers and others at Ground Zero after the attacks, encourages those affected to continue healing.
He says it is important never to forget and to "always reflect, remember and recall." But Jordan adds, "There is a time to move on and not wallow in an extended period of grief."
And at the Flight 93 ceremony near Shanksville, Biden adapted words from a poem by William Butler Yeats. He told the families that he hopes "you're able to sing more than you weep."
DiBlasio reported from Shanksville, Pa.; Dorell from Arlington, Va.
Contributing: Carolyn Pesce in McLean, Va.
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