Around the U.S., ceremonies commemorate the 25th anniversary of the Sept. 11th terror attacks in New York and at the Pentagon.

The spy agency released dozens of intelligence documents it had sent to Presidents Bill Clinton and George W. Bush, outlining what was known about Al Qaeda.

Flags will fly at half-staff Friday as Americans mark 25 years since 9/11. Here's what's open, what's closed and how the day is observed.

Several dozen presidential briefing documents declassified Friday, the 25th anniversary of the Sept. 11 attacks, detail intelligence government officials had gathered about Osama bin Laden and al-Qaida leading up to the hijackings that killed nearly 3,

Times photographers were on the scene and spread across the city to capture the attacks and their aftermath in images that are, to this day, too heart-wrenching to look at, and too important to look away from.

The resilience and patriotism amid a backdrop of destruction told the story of the shocking day in a single image. NBC News’ Stephanie Gosk reports.

What happens when a national day of mourning is also your birthday or anniversary? People born or married on September 11 talk about it.

25 years after the September 11 attacks, the New York Giants recall encountering the heroic passengers of Flight 93: "It really shakes you."