Remembering 9/11: Tributes to victims in New York, Pennsylvania and at the Pentagon

Pedestrians in lower Manhattan watch smoke billow from New York's World Trade Center on Tuesday, Sept. 11, 2001. (AP Photo/Amy Sancetta)

The Sept. 11, 2001 terrorist attacks on the U.S. by al Qaeda jihadists changed the future of security for not only Washington, but for nations on every inhabited continent worldwide — sparking the Global War on Terror that continues to this day.

More than 20 years have passed since 19 hijackers boarded four commercial flights and crashed into the Twin Towers in New York City, the Pentagon near Washington, D.C., and an empty field in Pennsylvania after passengers on United Airlines flight 93 thwarted what is believed to have been an attempt to strike either the U.S. Capitol or the White House. 

The plan, outlined by al Qaeda leader Osama bin Laden, killed 2,977 victims 23 years ago in what remains the largest terrorist attack in history and set in motion a global fight against extremism.

But despite the end to the U.S. war in Afghanistan and declared defeat over Islamic terrorist organizations like al Qaeda and the Islamic State, experts warn the threat posed by extremist groups remains acute to this day.

"The threat has evolved," Bill Roggio, senior fellow with the Foundation for Defense of Democracies and editor of the Long War Journal, told Fox News Digital. "It's certainly much more difficult to launch a 9/11 style attack, but there's much more opportunity for jihadists from both al Qaeda and the Islamic State to launch individual attacks, such as we've witnessed over the last decade and a half particularly. 

 "Prior to 9/11, al Qaeda was operating openly in Afghanistan and on cellular level, in dozens of countries. And now there are safe havens and battlefields with 10s of 1000s of fighters that exist throughout the world," he added.

It’s been 23 years since the most deadly attack on American soil and, in the wake of the commemoration of Sept. 11, 2001, one survivor who escaped from the North Tower of the World Trade Center is looking back at the resilience shown that day and encouraging a new generation of learners to listen in.

Michael Hingson, a best-selling author and keynote public speaker, was a computer hardware sales manager recruited in 1999 to open an office and manage a team of people on the 78th floor of 1 World Trade Center.

"We were going to be doing some sales training that day," Hingson told Fox News Digital during a video interview.

On a crisp, clear September morning, the entire world fixated on their televisions and radios in horror as four American planes hijacked by terrorists crashed into a field in Pennsylvania, the Pentagon and the Twin Towers in New York City.

"I was in my office. A colleague, David Frank, was also with me," Hingson said. "He was from our corporate office. The two of us were going to be doing these sales seminars."

At 8:46 a.m., American Airlines Flight 11 struck the North Tower.

"None of us knew what happened," Hingson said. "Tall buildings are made to flex in windstorms, and the building just started tipping and tipping."

"We actually moved maybe about 20 feet. David and I actually said ‘Goodbye’ to each other because we thought we were about to take a 78-floor plunge to the street. But then the building stopped flexing, and it came back and became vertical," he added.

There are 9/11 memorials throughout the United States where you can go at any time of the year to pay your respects to those who lost their lives on a tragic day in American history. 

There is a memorial in New York City where millions of visitors go each year to honor the fallen and educate themselves on the events of Sept. 11, 2001.

9/11 memorials have been built in states including Massachusetts, New York, Virginia, Pennsylvania and California.

An American flag is put on display Wednesday at the Pentagon to commemorate the victims of the 9/11 attacks.

An American flag has been unfurled at the Pentagon Wednesday ahead of the main observance ceremony there for victims of the Sept. 11 attacks.

Joint Chiefs Chairman Gen. Charles Q. Brown, Jr. is set to speak later this morning, followed by Defense Secretary Lloyd Austin.

American Airlines Flight 77 was hijacked and crashed into the Pentagon on 9/11, killing all 64 onboard and 125 in the Pentagon, the Department of Defense says.

The remains of the World Trade Center stand amid other debris following the terrorist attack on the buildings in New York on Sept. 11, 2001. (AP/Alexandre Fuchs)

Calls made from those inside the north and south towers on September 11, 2001, displayed great strength in the midst of tragedy. 

Listening to the phone calls that were made, bravery can be heard, as people did their best to assist one another through the horrific events. 

Radio calls from first responders, including Orio Palmer, show their incredible impulse to quickly come to the aid of those who were trapped inside the buildings, even though doing so put their own lives on the line.

Palmer was Chief of Battalion 7 and one of the first responders to the 9/11 attacks. Palmer was in impeccable shape, and used his strength to quickly climb up the tower. He managed to fix a broken elevator and a broken radio receiver, allowing the firefighters to once again communicate with one another about what they were seeing.  

He entered the south tower, fixed the elevator and took it all the way up to the 40th floor of the building. After that, he started to make the climb on foot. 

"Orio got up there pretty quick. Anyone who was wounded or dying, to know somebody was able to get up there, they knew there had to be a way out," Palmer's brother Stephen shared in the "9/11 Phone Calls from the Towers" documentary. "The people who were there at the point of impact to have seen him, I can only imagine there must have been some elation or euphoria that's probably indescribable. Just to see him and realize there's some hope here, thanks to this guy who just made it up here." 

David Paventi was on the 81st floor of the World Trade Center's North Tower when the first plane struck on 9/11.

A banker from Charlotte, North Carolina, Paventi was in New York City at the time on business. His company had a new office in the World Trade Center it was still moving into, with TV mounts screwed into the walls but TVs not yet installed.

The day before, Sept. 10, Paventi remembers looking out a window of the skyscraper on a day that was so muggy and foggy he couldn't see the streets below.

"There was another gentleman … that was up there with me that day — he and I had went and got coffee that morning and went upstairs — and I remember him saying to me, ‘How do airplanes not hit this building?’" Paventi recalled.

He didn't make much of the comment then, other than thinking there were air security and control methods in place to make sure that wouldn't happen.

The next day was a bright, crisp preview to autumn, Paventi said. Just before he and his team in the World Trade Center building were scheduled to start their morning meeting at a long table in a conference room on the 81st floor, American Airlines flight 11 hit the North Tower's 93rd floor, just 12 floors above Paventi's office, at 8:46 a.m.

He said it felt like what he'd imagine an earthquake feels like, even though he's never experienced one himself.

"I remember looking up … and the light was just shaking back and forth over the table," Paventi said. "So, my initial instinct was to get under the table because I didn't want the light to fall on my head. And as I was doing that, literally everyone in the conference room got up from their seats and took off out of the front of the room."

Flags and flowers are placed by the names of those killed during the Sept. 11, 2001, attacks, at the reflecting pools at the National September 11 Memorial & Museum, Tuesday, Sept. 10, 2024, in New York. (AP/Donald King)

Former President Trump and Vice President Kamala Harris both traveled to New York City following their first presidential debate showdown, to put politics aside and commemorate the 23rd anniversary of the 9/11 terrorist attacks. 

Wednesday marks the 23rd anniversary of the Sept. 11 attacks. Nearly 3,000 people died as the result of a group of terrorists launching coordinated attacks against the U.S. by hijacking and crashing commercial airline planes at the World Trade Center in New York City, the Pentagon in Washington, D.C., and Shanksville, Pennsylvania, in what became America’s most deadly terrorist attack.

Trump and Harris participated in their first presidential debate Tuesday night before they both traveled to New York City. 

First, Trump is expected to visit the World Trade Center site, also known as Ground Zero, to attend the 9/11 memorial commemoration where he is set to deliver brief remarks. 

Next, Trump is expected to visit New York Fire Department Engine 4, Tower Ladder 15. 

Meanwhile, President Biden and Harris are also expected to visit the 9/11 memorial for the commemoration ceremony. 

Biden and Harris are then expected to travel to Shanksville for a wreath-laying ceremony at the Flight 93 Memorial. 

Later, Biden and Harris will participate in a wreath-laying ceremony at the Pentagon in Arlington, Virginia.