Americans across the country paused Tuesday to mark the 11th anniversary of the Sept. 11 terror attacks in New York City, the Pentagon, and Shanksville, Pa.
Thousands gathered at the site of the World Trade Center in New York to pay their respects and hear the names of nearly 3,000 victims killed in the attacks read by mourning loved ones.
Families and friends clutched balloons, flowers, and pictures of their loved ones in a moment of silence at 8:46 a.m., the exact moment the first hijacked plane crashed into the northern tower and again to mark the crash at the second tower.
Matthew Walier, who lost his sister Margaret Seeliger on 9/11, said the anniversary is still painful.
''The feeling of hurt, my sister being murdered. It's just not something I can describe and put words to to be honest with you," he said.
A moment of silence was also observed at the Pentagon, and in Pennsylvania.
In Washington, Obama and first lady Michelle Obama attended a ceremony on the White House's south lawn.
Obama then laid a white floral wreath at the Pentagon, above a concrete slab that said "September 11, 2001 - 9.37 am."
The President assured family and loved ones of those who perished on 9/11 that their country would never forget them.
''We will never fully understand how difficult it has been for you to carry on, to summon that strength and to rebuild your lives. But 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. Your loved ones will never be forgotten," he said.
On Capitol Hill, the nation's lawmakers praised the many people who stood fast and gallantly in the hours after the attacks.
"Everyone kept their place. The professionals who did their duty, who ran in so others could run out," House Speaker, Rep. John Boehner said. "The patriots who banded together in the sky over Shanksville to save this Capitol and these steps. The volunteers who raised their hands, said 'I'll go, and now fight overseas in perilous conditions.'"
Vice President Joe Biden was in western Pennsylvania to attend the Flight 93 memorial service for the victims who struggled and died to avert the hijacked plane that went down in Shanksville.
Bells of remembrance were rung by surviving family members.
Across the country, this year's events were somewhat understated from past years with familiar ceremonies but also with a sense that it's time to move on.
The U.S. terror attacks were followed by years of war in Afghanistan and Iraq, where the U.S. military death toll years ago surpassed the 9/11 victim count.
The attacks on Sept. 11 were the worst terrorist acts committed in U.S. history.