Photos That Defined 9/11, and the People in Them—20 Years Later

She was on the roof deck, watching in disbelief as the towers collapsed. She felt grateful for her son, but vulnerable—and, she says, “hopeless about humanity.”

“I’m sorry to bring you into this crazy world,” she recalls thinking as she gazed at Vaughan.

Now an interior designer living in Fairfield, Conn., Ms. Piccirillo says the picture reminds her of the larger devastation of the day. “We are a little blip on the map of those people who lost lives,” she says.

It also reminds her that the future for her son turned out better than she could have seen at the time.

Vaughan Piccirillo-Sealey

was about 11 when his mom told him that he was in a well-known photo from 9/11 by

Alex Webb,

a photographer with Magnum Photos. “It was kind of surreal. ‘Is that really me?’ ” he recalls thinking.

As he grew older, the photo made more of an impression on Vaughan, now a student at the University of Connecticut. He noticed how his mother had placed his carrier so he was facing her and not the terrible scene across the river. And she is looking at him.

“Obviously my mother cares about me and my well-being and put me above the tragedy at hand, and I think a lot of parents would have done the same,” he says.

“It’s a good message,” he adds. “You have a choice to decide which narrative to point your eyes at, and I think my mother chose the ones of love and care over despair.”

Photographer

Gulnara Samoilova

started running as the South Tower collapsed. Even 20 years later, it’s hard for her to talk about that moment. She was pregnant at the time and fell as she tried to flee. “I thought I was going to be buried alive,” she says.

She got up, lifted her camera and started shooting, putting the lens between herself and this horrible unfolding reality. People looked like silhouettes in the dark, thick air.

In one of her first shots,

Jonathan Markowitz

(seen in the photo with a shirt covering his mouth) walks with some of his co-workers after they escaped the North Tower of the World Trade Center.

Mr. Markowitz, then 46, was based in the Chicago area as a partner of SMW Trading Company and regularly traveled to New York to visit its office on the North Tower’s 85th floor. He had called his wife,

Ruth Wenger,

that morning to let her know he was on schedule to be home in Evanston, Ill., that night in time for parent-teacher conferences.

He was in a conference room at 8:46 a.m. when he heard a huge bang, felt the building sway and learned from an co-worker that a plane had just hit.

He and his colleagues began moving down the stairs, which grew hotter and more crowded by the minute, but the descent was orderly. Rumors circulated in the stairwell, but information was limited and they didn’t know a second plane had hit.

About 90 minutes later he was downstairs on the concourse level and feeling relieved, before someone yelled, “Get down!” He took cover behind his favorite smoothie stand as a floor-to-ceiling wall of dust and debris barreled toward him. Unbeknown to him at the time, that maelstrom was the South Tower collapsing.

Then the noise stopped and the lights went out. Dust choked the air, and he grabbed his blue shirt from the small suitcase he had carried down.

Mr. Markowitz called out to his colleagues

Rob Leder

and

Bill Forney,

and they all got up to walk toward an exit to the street, helped by someone with a flashlight. Outside resembled a black-and-white horror film, Mr. Markowitz recalls, with dust covering everything and office papers littering the ground like a giant ticker-tape parade.

“My job at that point was to get home,” says Mr. Markowitz, who is now 66 and works for a different trading company.

He never made it to the parent-teacher conference. But the effect on his family life was long lasting. There were more family vacations. And nearly any time his kids want to spend time with him, he’ll change plans to do it.

“You never know when you’ll have that moment,” he says. “That next chance may not be there anymore.”

Michael B Sauer

had been enjoying a day off from his job as a customs officer at JFK airport when he saw the news of the attacks. The 34-year-old volunteer firefighter rushed to Ground Zero to help with search and rescue efforts.

Mr. Sauer, now 54, gets choked up when he talks about that day he spent searching for signs of life in what firefighters dubbed “the pile.” He heard car alarms and the distinct sounds of police and fire strobe lights coming from vehicles buried under the rubble.

“You’re walking around and listening for anyone banging or any sign of life,” Mr. Sauer recalls. “That’s what you’re there for, to try to help and hopefully get someone to safety.

“Body over here!” he recalls yelling to other rescuers at one point.

“Dead or alive?” others asked.

“Dead.”

And that is how it went all day as he scoured the pile with a friend, another volunteer firefighter. “We didn’t find anybody other than the parts we found,” he says.

They traversed the peaks and valleys of the pile as wind blew ash into their eyes and throats. Mr. Sauer and his colleague were hours into the day when they stumbled onto a fire hydrant, a welcome sight.

“It wasn’t like there was a water fountain you could go to,” Mr. Sauer recalls. “This thing was just standing out there by itself with water coming out of it.”

Mr. Sauer was rinsing the grit from his mouth when he looked up and saw someone taking his picture.

He returned to his job at the airport the next day, though he volunteered again to sift for evidence at a Staten Island landfill where the Ground Zero debris was taken. By 2006, he took a role, which he still holds, in a new post-9/11 antiterrorism program at U.S. Customs and Border Protection.

The attacks “put a flame under our ass to just really do our job above and beyond to protect,” Mr. Sauer says.

He’s still a volunteer firefighter, as are his sons, ages 18 and 20, and at least once a year, around the 9/11 anniversary, he sends a text to

Yoni Brook,

the photographer who took his picture at the hydrant.

“We have this bond,” Mr. Sauer says. “It’s just a bond of that day, and him putting me in history.”

“To me it feels like it was just the other day,” he adds. “Not a day goes by that I don’t think about it.”

Joanne “Jojo” Capestro

hadn’t felt well that Tuesday morning, so she arrived at work with a cup of takeout tea. A sudden jolt made her spill it, and she felt the building sway. All the phones were ringing. Her first thought was that she needed to clean up that tea.

Then 39, she was a sales assistant at May Davis Group, a brokerage and investment banking firm on the 87th floor of the North Tower, about six floors down from where a plane rammed into the building. She and colleagues started down the stairs, although her co-worker, stockbroker

Harry Ramos,

stopped on the 30th floor to help someone. “I’ll meet you outside,” Ms. Capestro recalls him saying.

Life had changed drastically. Just the night before, Ms. Capestro had been watching a reality TV show with friends at her apartment in Brooklyn. And just that morning, she had joked with Mr. Ramos, a new homeowner who had come in with a sunburn from mulching over the weekend.

Ms. Capestro made it outside just as the South Tower collapsed. She screamed and dove under an SUV. “Everything was white when I opened my eyes,” she recalls. “I really thought I had died.”

She saw badly injured people, and then a colleague, and the pair clung to one another. She was desperate to know where her other co-workers were. That is when photographer

Phil Penman

snapped the photo.

All the May Davis employees made it out except Mr. Ramos.

Her survivor’s guilt still lingers, Ms. Capestro says. In the aftermath of 9/11, she hid at home, glued to the TV.

“I was really, really, really in bad shape,” she says. “It took me months to wake up and say, ‘I’ve got to put my best foot forward.’ ” She is now an executive assistant at Oppenheimer & Co.

In 2014, Ms. Capestro donated her dust-caked clothes from that day to the 9/11 Memorial & Museum. After Mr. Penman shared all his work with the site, a curator recognized Ms. Capestro in his photos and introduced the two.

Ms. Capestro cried when she met the photographer. She says she is grateful that he documented her experience, especially as 9/11 recedes further into the past.

“When you tell people you were in the World Trade Center, they say, ‘Oh, across the street?’ ” Ms. Capestro says. “They don’t realize what I went through. They don’t realize what I saw.”

When she got married in 2018, she asked Mr. Penman to photograph her wedding.

“Phil was with me on the worst day of my life, and Phil was with me on one of the best days of my life,” she says.

Srinath Jinadasa

(wearing a jacket in the photo), an engineer for the Port Authority of New York and New Jersey who worked on the 74th floor of the North Tower, did one task before fleeing: He watered the geraniums on the window sill in his office.

At that moment, Mr. Jinadasa, now 79, says he didn’t realize the scope of the attack. He thought he might be living through something similar to the 1993 World Trade Center bombing, which had put him out of his office for months, and the plants had died. He didn’t want that to happen again.

“Under the circumstances, one doesn’t think logically, I guess,” Mr. Jinadasa says. “You do things that don’t make sense.”

The married father of two got down the stairs quickly. When he saw a cloud of dust and flying debris coming toward him in the concourse, he thought he was going to die.

“I’m still here,” he recalls thinking with surprise after the wave of dust stopped.

He made his way outside, stopping to rinse out his eyes at an ambulance that was distributing water. Dazed and dirty, Mr. Jinadasa, a colleague and another man walked on as Mr. Penman, the photographer who also captured Ms. Capestro, snapped a photo.

Mr. Jinadasa trekked several miles uptown to Penn Station and caught a train home to New Jersey. “For the next few days I was uneasy, and I had to kind of pace up and down,” he says. “I could not sit in one place.”

He returned to his job at the Port Authority—in a different office—helping to restore the train service that the attacks had disrupted. “I was just thankful to still be around,” he says.

He retired in 2012 and now lives in Jacksonville, Fla. He says 9/11 is never far from his thoughts, although he is uneasy with “the many things that have happened on the back of that event,” including the war in Afghanistan that the U.S. launched in response to the attacks and ended little more than a week ago.

The photo hangs in Mr. Jinadasa’s home. He says it elicits in him a combination of feelings: the reality that he came close to dying on 9/11, and the reality that time marches on.

Dominic Guadagnoli

was at his desk when a loud bang reverberated through the federal courthouse in lower Manhattan.

Mr. Guadagnoli was a deputy U.S. Marshal at the U.S. Marshals Service office, several blocks from the World Trade Center. He ran out to the street in time to see a woman run by, yelling, “Someone flew a plane into the Trade Towers!”

Mr. Guadagnoli and a co-worker soon rushed to the scene. “Everyone who had a badge was out there doing something,” he says.

Where to be of most use? Mr. Guadagnoli stood between the two towers, and saw some people jumping or falling from them. “I can’t do anything here,” he told himself.

So he and a co-worker turned their attention to directing and helping the waves of people coming out of the towers. Some were just shaken while others had gashes and wounds. He would escort them to a nearby triage area and then go back to help other survivors.

At one point, Mr. Guadagnoli spotted two men, themselves weary-looking evacuees, holding up a woman who was almost collapsing. Mr. Guadagnoli stepped in and scooped her up. Ms. Samoilova, the photographer who also photographed Jonathan Markowitz that day, captured the image.

The woman, Mr. Guadagnoli would learn later, was

Donna Spera.

She had been waiting for an elevator on the 78th floor of the South Tower, right in the line of impact from the second plane strike. People around her had died. She’d been thrown and had walked downstairs in pain, Mr. Guadagnoli says.

“Don’t let go of me, don’t let go of me,” Mr. Guadagnoli recalls her saying.

He told her she would be OK and would see her family soon. “I was trying to make conversation in the middle of hell,” he recalls. He carried her 50 or 60 yards and then helped an EMT put her in an ambulance. He watched it pull away and then went back to assisting other people.

Shortly afterward, he heard a huge crack and saw the South Tower come roaring down.

Falling debris cut his head and his cornea, and he wound up at the hospital, where doctors put a patch on his eye. That night at home, he couldn’t sleep and sat in the dark listening to the fire engines still heading to Ground Zero.

“All I could think about was her,” he recalls. Had the ambulance carrying Ms. Spera made it?

Through contacts, he was able to learn that she had survived. He later met her and her husband for lunch.

“For a long time I had three triggers: airplanes, fire-engine sirens and any loud bang or noise,” Mr. Guadagnoli says. “It would startle the hell out of me. I would just shake.”

He’s now 52 and living in Pensacola, Fla. He has retired from the U.S. Marshals Service and is doing court security work. Therapy has helped him process his experience, he says, but he feels on edge around the anniversary of the attacks.

Every 9/11, he sends flowers to the woman he carried to safety.

Shannon Stapleton

was a freelance photographer when he got a call he would never forget. A Reuters editor calmly requested he head to the World Trade Center. A plane had struck.

“Sure,” Mr. Stapleton, then in his early 30s, replied, envisioning a sightseeing plane.

He happened to be at another job, in Times Square, and started to wrap up. He saw people outside staring up at the jumbotron and footage of the top of the first-hit tower burning. He realized he needed to move fast.

By the time he got to lower Manhattan by subway, another plane had struck. “I’m about to cover probably the biggest story of my lifetime, right in my backyard,” Mr. Stapleton recalls thinking.

He took pictures of people fleeing and the South Tower collapsing. He ducked into a stairwell to shield himself from the dust and shards coming at him, and then continued shooting.

That’s when he saw somber-faced emergency responders walking toward him, carrying someone from the rubble. Mr. Stapleton could tell the man was dead, but he didn’t know the victim was Father

Mychal Judge,

the longtime chaplain of the New York Fire Department.

“I had a feeling right away that he was important,” he recalls, adding that he noticed how “a lot of different agencies were all trying to carry this man amongst the tragedy.”

His digital camera, which he had recently purchased to make himself more marketable, allowed him to view his photos quickly. He thinks that the camera may have saved his life: Had he not known for certain that he already had solid shots, he might have tried to go deeper into the building.

He started thinking about his wife, who was pregnant, and it occurred to him that the other tower could collapse. He was about two blocks away when it did.

“Are you all right?” Mr. Stapleton recalls his editor asking when he got back to the Reuters office. “I was covered in soot and dust. I said, ‘Define what all right means.’ ”

Mr. Stapleton returned to Ground Zero that day and worked nonstop covering the aftermath. He still didn’t know who was in his photo until several days later. By then, the image and stories of the chaplain were circulating.

“I started to learn who he was, what an incredible man he was and his legacy,” Mr. Stapleton says.

Soon afterward, he says, he received a letter at the Reuters office from Father Judge’s twin sister and his niece.

“It made me cry,” Mr. Stapleton recalls. “They were thanking me for risking my life and taking this photograph for the world to see what an incredible person he was.”

Many have called the photo a modern-day Pietà. “It was heavenly,” he says of the image. “He looks like what I could presume an angel would look like. It was surreal.”

Now 52 and a Reuters photographer, Mr. Stapleton is still covering “a lot of death and destruction and heartache and tragedy,” he says. He still thinks about Father Judge.

“Every now and again, I think something happens to me that will lift me out of that despair or funk that I’m in—the darkness,” he adds. “Sometimes I think that it’s him.”

—Elissa Curtis and Jim Oberman contributed to this article.

Write to Jennifer Levitz at jennifer.levitz@wsj.com