9/11's 15th anniversary: how America is remembering

Fifteen years after the deadliest terror attack in the US, Americans are gathering to honor the nearly 3,000 lives lost. 

Fifteen years after the deadliest terror attack in the United States, Americans across the nation are paying tribute to the thousands of lives lost on Sept. 11, 2001.

On Sunday morning, the families of some of the 2,977 victims gathered at the World Trade Center site in New York City for the annual reading of the names of the deceased. Those named included people killed in plane crashes in New York; Arlington, Va.; and Shanksville, Pa, on Sept. 11, 2001, as well as six victims of the 1993 World Trade Center bombing. 

The number of attendees at the ceremony has decreased over the years, as "parents of the deceased are getting older, younger people usually can’t make it because of work obligations," Tom Acquaviva, whose 29-year-old son was killed on 9/11, told USA Today prior to the event. "But I hope this year you will see a lot more people than previous years."

The reading paused six times to mark significant moments: when the first plane struck the World Trade Center's North Tower, when the second plane hit the South Tower, when Flight 77 crashed into the Pentagon, when the South Tower fell, when Flight 93 crashed into a field in Shanksville, and finally, the collapse of the North Tower.

At 8:46 a.m. EDT, the moment when the first plane hit the North Tower, houses of worship across the city tolled their bells as the crowd had a moment of silence. 

While some additional music and readings were added for Sunday's ceremony to mark the 15th anniversary, the event has remained largely the same over the past fifteen years. 

"This idea of physical transformation is so real here," Sept. 11 memorial President Joe Daniels said this week, in reference to the changed landscape surrounding Ground Zero. But on the day itself, "bringing the focus back to why we did all this – which is to honor those that were lost – is something very intentional," he said, as reported by Time. 

While New Yorkers commemorated the day by reading names aloud, thousands more gathered at similar memorial ceremonies at held at the Pentagon, in Pennsylvania, and in a plethora of other cities across the country to pay tribute to lives lost. A moment of silence was heard around America at 8:46, the time when the first plane struck. 

On Saturday, one day prior to the anniversary, bicyclists rode along the newly opened Sept. 11th National Memorial Trail in Pennsylvania, beginning at the Flight 93 National Memorial. Speaking at a ceremony on Saturday, trail alliance chief executive officer and president David Brickley said the trail was meant to honor those who died in the terror attacks.

"We're going to be stronger, more resilient," he said, according to the Daily American. "That's what this is about."

For many, the tributes on Sunday meant setting aside political differences in the midst of one of the most polarizing presidential elections in recent American history. Hillary Clinton and Donald Trump were in attendance at the New York ceremony, but, as per tradition, did not speak. Both candidates also kept with the tradition of not airing campaign ads on Sept. 11. 

"I think it is disturbing that a lot of that feeling of unity seems to be wavering these days," said Peter Guza of Massachusetts, whose father, Phil, was killed in the World Trade Center, to the Boston Globe. "The perspective that I created coming out of Sept. 11 is more focused on appreciating those who are still here, and how privileged we are to have them and to be in this country."