NEW YORK — With solemn ceremonies and prayers, moments of silence and the ringing of bells, the nation Sunday marked the 15th anniversary of the Sept. 11 terrorist attacks that killed nearly 3,000 people and forever changed how the United States views itself and its place in the world.
Commemorations unfolded in New York and outside Washington, where hijackers piloted planes into the World Trade Center and Pentagon, and at a rural field in Pennsylvania, where a plane crashed after passengers fought back against their hijackers.
"As Americans, we do not give in to fear," President Barack Obama said at the Pentagon Memorial service as about 800 family and friends of those who died stood for 30 seconds of silence at 9:37 a.m. Eastern Daylight Time, the same time that a jetliner struck the building and killed 184 people.
Defense Secretary Ashton Carter and Joint Chiefs of Staff Chairman Joseph Dunford joined Obama in placing a wreath of white lilies in the memorial garden.
"The most enduring memorial to those we lost is ensuring the America we continue to be, that we stay true to ourselves, stay true to what is best in us, that we not let others divide us," Obama said.
A military band played America the Beautiful.
Both major presidential candidates attended the ceremony in lower Manhattan, but Democratic nominee Hillary Clinton left early, after about an hour and a half; she felt overheated, according to a statement from campaign spokesman Nick Merrill.
The New York ceremony started with a moment of silence at 8:46 a.m., coinciding with the time the first plane struck the north tower. Some bowed their heads while others held high photos of their loved ones.
Then began the lengthy process of reading out the names of the victims. Family members came to the stage in pairs to read them out and sometimes add a heartfelt message about the victims.
Jeremy D'Amadeo was 10 when his father, Vincent, was killed at the World Trade Center, and he spent many summers at a camp for children of 9/11 victims.
"This summer I had the privilege of working with kids who had their own tragic loss, kids of Sandy Hook," D'Amadeo said. "These kids lifted me up and made me know that I wanted to give back as much as I can.
"Sometimes the bad things that happen in our lives put us on the paths we should be going, to help others as much as we can. P.S, Dad, I love you."
At the Flight 93 National Memorial in southwestern Pennsylvania, the ceremony included music, the reading of the names of the 40 victims who died there and the ringing of bells.
The testimonials on Sunday went well beyond the official ceremonies. Tourists crowded the memorial fountains built into the footprints of the two original World Trade Center towers.
Some people left roses and mini American flags on the fountains' black granite edges, where the names of victims are engraved.