AMNA NAWAZ: Welcome to the "News Hour."

Families, survivors, first responders, and dignitaries spent much of this day marking the 25th anniversary of the 9/11 attacks with somber and poignant ceremonies.

GEOFF BENNETT: That included major gatherings in New York, a memorial attended by President Trump at the Pentagon, and a service in Shanksville, Pennsylvania.

The September 11 attacks killed 2,977 people and sent the country on a course that would define the next quarter-century.

BOY: On behalf of Atay (ph), Kuya (ph), and Dee Dee (ph), thank you for being our guardian angel.

We love and miss you.

GEOFF BENNETT: Where the Twin Towers once touched the sky, this morning names of the dead echoed in memorial.

MAN: Brandon J. Buchanan.

WOMAN: Greg J. Buck.

MAN: Dennis Buckley.

GEOFF BENNETT: Each one a testament to a life cut short 25 years ago.

MAN: These were full three-dimensional people.

And if they were here today, I think they would prefer that we remember them for how they lived versus how they died.

WOMAN: Jacqueline (ph).

GEOFF BENNETT: Family members read out each name over roughly four hours, accompanied by music, moments of silence, and bell ringing... (BELL RINGING) GEOFF BENNETT: ... to mark when the four planes crashed and two towers fell that day; 25 years ago, New York was the first place struck in the attacks, shocking the city and the nation.

American Airlines Flight 11 flew into the World Trade Center's North Tower at 8:46 a.m.

A second plane, United Airlines Flight 175, followed at 9:03.

Roughly 30 minutes later, another plane, American Airlines Flight 77, crashed into the Pentagon, creating a fireball.

And at 10:03, United Flight 93 went down in Shanksville, Pennsylvania, after its passengers fought back against the hijackers.

By the end of the hour, the Twin Towers had collapsed and the country was forever changed.

(BELL RINGING) GEOFF BENNETT: Those paying tribute at Ground Zero today included every living former president and first lady, Vice President J.D.

Vance, and New York City Mayor Zohran Mamdani.

(SINGING) GEOFF BENNETT: The moment was first marked at the Pentagon at dawn when a flag was unfurled.

MAN: Barbara K. Olson.

GEOFF BENNETT: Hours later, President Trump spoke at a memorial service for the 184 men and women who died in that attack, praising the sacrifice of the U.S.

military.

DONALD TRUMP, President of the United States: In 25 years, a generation has passed since the terror attacks of September 11, 2001.

Yet time has not dimmed the honor of that day when our country came face-to-face with true evil.

GEOFF BENNETT: Condoleezza Rice, President George W. Bush's national security adviser on September 11, spoke as well.

CONDOLEEZZA RICE, Former U.S.

Secretary of State: But I will always carry deep personal remorse for the pain that you, the families of the fallen, still feel and for the trauma that our country endured.

(BELL RINGING) GEOFF BENNETT: And, in Shanksville, bells and speeches honored the 40 lives lost on United Airlines Flight 93.

One notable contrast to ceremonies of the past, more explicit political remarks in some cases, including President Trump, who tied support for the Iran war to the memory of 9/11.

DONALD TRUMP: We will never, ever forget.

That's why we fight today.

We don't have a choice.

There can only be victory.

We fight hard.

We fight to win.

GEOFF BENNETT: And in Manhattan, the relatives of two victims accused the government of withholding information about the role Saudi Arabia played in the attacks and called for accountability.

TERRY STRADA, Widow of 9/11 Victim: For 25 years, administration after administration, including leaders in front of us here today, chose to protect the Saudis, instead of standing with the 9/11 families.

(CHEERING) GEOFF BENNETT: Though 15 of the 19 hijackers were Saudi nationals, the Saudi government has consistently denied any involvement in 9/11.

Many of those gathered urged a return to the national sense of unity that followed the attacks.

GREG CARAFELLO, 9/11 Survivor: The camaraderie you had after 9/11 was amazing.

And I don't know -- the young people have not experienced.

They have only experienced the bitter polarization and so on.

GEOFF BENNETT: Today, more than a quarter of all living Americans, roughly 100 million people, were not yet born on September 11, 2001.

For Sonia Argon, a recovery worker at Ground Zero, that made the act of remembering this year more important than ever.

SONIA ARGON, Ground Zero Recovery Worker: And it's 25 years later, and we have a bunch of people that still don't understand.

And my mission is to help them understand that they inherited this world and what's normal for them is abnormal for us.

Today is a hard day.

I don't know why it's harder than any other year.

I just feel people are forgetting.

And they can't.

They shouldn't.

GEOFF BENNETT: And, today, the CIA released its largest ever batch of declassified presidential intelligence briefs on the threat from Osama bin Laden and al-Qaida before 9/11.

Among the 71 documents is a September 1998 brief warning that Osama bin Laden's preferred option is to strike the U.S.

on its own soil in Washington, adding that al-Qaida may fly an explosive-packed airplane into a U.S.

city.

The documents show both the Clinton and Bush administrations received repeated warnings, but experts say they do not fundamentally change what was known.

The threat was clear, while the intelligence lacked the timing and specifics needed to identify the coming attack.