9/11 25th anniversary ceremony: Families gather at WTC, Pentagon, Shanksville

Former Sarasota, Florida, second grade student Krystal Davis remembers a wave of confusion washing over her and her classmates on the morning of Sept. 11, 2001, after a suited man whispered into the ear of the president of the United States, who was seated just in front of the students.

Then-President George W. Bush was visiting Emma E. Booker Elementary School and had been listening intently to the children in Mrs. Sandra Daniels' second-grade class flexing their reading skills, when the look of admiration on his face suddenly gave way to an expression of concern.

Chief of Staff Andrew Card had just relayed to Bush that a second plane had crashed into the World Trade Center in New York City. "America is under attack," he later recalled whispering to the president.

"You could see the shift with [the president] once he got the message, and then you could see it on his face," Davis said in an interview with ABC News commemorating 25 years since the 9/11 attacks. "And then the shift of him going back to his normal self and smiling like, 'I don't want to alarm the kids.'"

MORE | Students with President George W. Bush on 9/11 reflect on the day: 'You could see it on his face'

Twenty-five years after Sept. 11, 2001, a group of New York City firefighters, who were stationed together on the Upper East Side, continue to honor the memories of colleagues lost in the attacks through the preservation of historic firehouse riding lists.

The firefighters began their careers at a firehouse on East 85th Street and were assigned there on 9/11. Now among a shrinking number of firefighters still serving from that era, they recently returned to the firehouse where their careers began.

While the firefighters joke that they have grown "a lot grayer" over the years, they said their memories of Sept. 11 have not faded. They worried, however, that another important reminder of that day could disappear.

Historic riding lists preserved behind glass are helping to keep the memories of nine firefighters alive 25 years after Sept. 11.

In firehouses across the country, firefighters maintain chalkboard riding lists that display the names of those on duty. The lists are updated regularly. Following the collapse of the World Trade Center towers, nine firefighters from their firehouse were unaccounted for. Their names remained on the riding list board.

They're not just names on a board. They're nine men who rushed in when everyone rushed out. Each name represents a life and a story, from the longtime captain in charge to the police officer turned firefighter and the father who had twin babies at home. There's a story behind each one.

With the help of experts from the Metropolitan Museum of Art, the chalkboard from that day has been repaired and preserved.

The firefighters said preserving the riding lists, and the memories they represent, is an important responsibility for those who remain.

Captain James Schneider still remembers the moment he learned the World Trade Center had been struck on Sept. 11, 2001.

Schneider, captain of the fishing boat James Joseph II, had taken customers out on the water that morning and dropped anchor in Norwalk, Connecticut, when his brother, an NYPD detective, called to tell him the North Tower had been hit by a plane.

Krista McNally has more on the recollections of the fishing boat captain.

Shortly afterward, Schneider heard a Coast Guard radio call and decided to head toward Manhattan. After dropping off his passengers, Schneider assembled a crew of 13 and made his way toward New York City. Along the route, he witnessed the collapse of the Twin Towers.

Schneider joined a massive flotilla of police boats, tugboats, ferries, yachts and other vessels that responded to the emergency as about 150 boats descended on Manhattan to assist with evacuations.

Despite his role in the rescue effort, Schneider said he does not view his actions as extraordinary.

"Well, it's so difficult me to say anything that I did anything important because it's our responsibility to help. We're not going to turn our backs on anybody on the water," Schneider said.

Many people don't know there was a daycare inside the Pentagon. Over 100 children, including infants, survived after being evacuated.

Some of them, like Captain Hanna Born, were inspired to serve their country.

Born was two weeks shy of her third birthday when American Airlines flight 77 crashed into the Pentagon on September 11, 2001. The toddler was inside the daycare center with her sister who was an infant.

Nina Pineda speaks to Captain Born.

Her mother, Dana Born, was a Lieutenant Colonel at the time and was across the Potomac River at Bolling Air Force Base.

Captain Born and her baby sister were picked up by their dad, Marine Corps Lieutenant Colonel Tim Born, and wouldn't be reunited with their mother for days.

Their experience propelled them into enlisting.