NEW YORK — Americans commemorated 9/11 with solemn remembrances and vows to “never forget” 18 years after the deadliest terror attacks on American soil.

A crowd of victims’ relatives assembled at ground zero, where the observance began Wednesday with a moment of silence and tolling bells at 8:46 a.m. — the moment when a hijacked plane slammed into the World Trade Center’s north tower.

“As long as the city will gift us this moment, I will be here,” Margie Miller said at the ground zero ceremony, which she attends every year. She lost her husband, Joel.

“Because I feel like if we don’t come, they don’t need to do it. And I want people to remember,” said Miller, of Baldwin, on Long Island. After so many years of anniversaries, she has come to know other victims’ relatives, and to appreciate being with them.

“There’s smiles in between the tears that say we didn’t do this journey on our own. That we were here for each other. And that’s the piece that I think we get from being here,” she said.

President Donald Trump is expected to join an observance at the Pentagon. Vice President Mike Pence was scheduled to speak at the third attack site, near Shanksville, Pennsylvania.

Former President George W. Bush, the commander-in-chief at the time of the 2001 attacks, is due at an afternoon wreath-laying at the Pentagon.

The nation is still grappling with the aftermath of 9/11 at ground zero, in Congress and beyond. The attacks’ aftermath is visible from airport security checkpoints to Afghanistan. A rocket exploded at the U.S. embassy as the anniversary began in Afghanistan, where a post-9/11 invasion has become America’s longest war.

The anniversary ceremonies center on remembering the nearly 3,000 people killed when hijacked planes rammed into the trade center, the Pentagon and a field near Shanksville on Sept. 11, 2001. All those victims’ names are read aloud at the ground zero ceremony.

But there has been growing awareness in recent years of the suffering of another group of people tied to the tragedy: firefighters, police and others who died or fell ill after exposure to the wreckage and the toxins unleashed in it.

While research continues into whether those illnesses are tied to 9/11 toxins, a victims compensation fund for people with potentially Sept. 11-related health problems has awarded more than $5.5 billion so far. Over 51,000 people have applied.

After years of legislative gridlock, dwindling money in the fund and fervent activism by ailing first responders and their advocates, Congress this summer made sure the fund won’t run dry . Trump, a Republican and a New Yorker who was in the city on 9/11, signed the measure in July.

The sick gained new recognition this year at the memorial plaza at ground zero, where the new 9/11 Memorial Glade was dedicated this spring.

The tribute features six large stacks of granite inlaid with salvaged trade center steel, with a dedication “to those whose actions in our time of need led to their injury, sickness, and death.” No one is named specifically.

Some 9/11 memorials elsewhere already included sickened rescue, recovery and cleanup workers, and there is a remembrance wall entirely focused on them in Nesconset, on Long Island. But those who fell ill or were injured, and their families, say having a tribute at ground zero carries special significance.

Meanwhile, the Pentagon announced Monday that its 9/11 memorial will close next week for electrical and lighting work. The project, expected to take until late May, includes repairs to lighting glitches in the shallow reflecting pools under the memorial benches.

Sept. 11 is known not only as a day for remembrance and patriotism, but also as a day of service. People around the country continue to volunteer at food banks, schools, home-building projects, park cleanups and other charitable endeavors on and near the anniversary.

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