Vice President Kamala Harris and former President Donald Trump shook hands again Wednesday morning as they arrived at the 9/11 anniversary ceremony in downtown Manhattan.

While investigators worked to identify and apprehend the 9/11 perpetrators, Osama bin Laden was committed to assassinating the U.S. president.

Twenty-three years after Sept. 11, 2001, illnesses linked to the World Trade Center attack have now killed more FDNY members than were killed on the day itself.

Defense Secretary Lloyd Austin revokes plea deal for alleged 9/11 mastermind Khalid Sheikh Mohammed and two others.

Three of the five 9/11 defendants at Guantanamo have reached a plea agreement with prosecutors, the Department of Defense announced Wednesday.

Ron DeSantis attended a 9/11 commemoration ceremony at ground zero in New York City on Monday, appearing with more than a dozen people who lost family on Sep. 11

Lt. Gen. Marc Sasseville speaks with Martha Raddatz about retiring from the from the U.S. Air Force and reflects on the moment he was asked to stop hijacked Flight 93.

Firefighter Bob Beckwith, remembered for standing with President George W. Bush in an iconic photo at the World Trade Center site in the days after 9/11, has died.

The medical examiner's office announced Thursday it has positively identified a 9/11 victim's remains.

Republican presidential candidate Vivek Ramaswamy commemorated the 22nd anniversary of the Sept. 11 terrorist attacks after he got criticized for past comments over them.

Former VP Mike Pence said Biden should have been in New York or at the Pentagon.

Twenty-two years after the Sept. 11, 2001, terrorist attacks, the New York City's Office of the Chief Medical Examiner has positively identified two more victims.

The New York City Fire Department has added 43 new names to its World Trade Center Memorial Wall.

Luke Laidley, a 9/11 survivor and dad of three, died on July 4 after jumping into Lake Michigan to help kids struggling in the water.

George Santos has invited a former ground zero volunteer firefighter Michael Weinstock to President Joe Biden's State of the Union address on Tuesday

The National Archives disclosed declassified notes from a 2004 interview.

A New York City paramedic who responded to the terrorist attacks on Sept. 11, 2001, will be laid to rest on Wednesday, six days after she was stabbed to death.

Twenty-one years after the Sept. 11 attacks, forensic scientists are still hard at work identifying remains found at Ground Zero.

A former MLB pitcher who retired and became a Port Authority police officer died in a car accident on his way to a Sept. 11 memorial ceremony on Sunday in New York City.

9/11 rescue dogs' best friends were the people who kept dogs safe at Ground Zero .

Shannon Stapleton and Kayla Bergeron have bonded over tragedy.

Former President George W. Bush spoke at the Sept. 11 memorial at Shanksville, Pennsylvania, to mark the 20th anniversary of the attacks Saturday.

The 9/11 attacks set off a wave of Islamophobia in America that many peaceful and patriotic Muslims say still reverberates years later.

Victims' families observed the pretrial proceedings this 20th anniversary.

On 20th anniversary of 9/11 attack, questions, anger, revenge and death yet linger

Of the 15 people who left from Engine 54, Ladder 4 that day, none returned home.

Biden will attend three 9/11 memorials on the 20th anniversary of the attacks on Saturday.

The day before the 20th anniversary of the 9/11 terrorist attacks, a pretrial hearing against five accused orchestrators was held Friday with none of them present.

Joseph Reina grew up never knowing his father but carries his name.

Part 5 of ABC News' series on 9/11 examines how police departments became the front line of defense in the War on Terror, leading some to face charges of over-policing.

On Sept. 11, 2001, rookie F-16 pilot Heather Penney was tasked with flying into hijacked flight 93 to stop it before it reached Washington, D.C.

Part 4 of ABC News' series on 9/11 looks at Guantanamo prison, which was used to detain suspected terrorists but came to symbolize America's conflicted response to 9/11.

The hijackers were late for their flight, but because they were full-fare, first class passengers, the agent went above and beyond to ensure they made their flight.

Part 3 of ABC News' five-part series on the 20th anniversary of 9/11 looks at the "forever wars" that resulted from the attacks -- and whether they were worth it.

Part 1 of ABC News' five-part series on the 20th anniversary of 9/11 looks at the ongoing questions of how the attacks could happen -- and who was responsible.

Nearly half say the U.S. has changed for the worse since the attacks, according to a new ABC News/Washington Post poll.

Of the last 25 people who made out of the World Trade Center's south tower on Sept. 11, 2001, Florence Jones was number 18.

The judge dismissed the court several hours ahead of schedule to allow both sides to regroup and strategize.

Khalid Sheikh Mohammed and four other 9/11 defendants are set for pretrial hearings.

Even before the 9/11 attacks, the Secret Service was starting to modernize the way it did business