This story is part of TODAY's series "Survivors: What Happens After the Headlines Fade." For more stories and videos from the series, click here.
Sept. 11, 2001, was a crisp, clear day, as Clarence Singleton remembers it. Singleton, who had retired the previous year from his job as a lieutenant firefighter with the New York City Fire Department, was about to leave his apartment when he turned on the radio and heard that a plane had hit one of the towers at the World Trade Center.
Singleton, now 69 and living outside of Richmond, Virginia, had rescued civilians during the 1993 World Trade Center bombing, and while the alert gave him pause, he continued on with his day.
"(Then) I heard a second announcement over the radio, and it said that a second plane had hit the tower," Singleton remembered. "I knew right away that something was going on, something was planned. I went back to my apartment, and I donned a fire department T-shirt, pair of jeans and a pair of boots to go over to the scene."
As Singleton rode the subway from Brooklyn into Manhattan, people recognized his FDNY gear.
"They asked me if the tower was gonna collapse. ... I said, 'Nah, I've fought fires in high-rise buildings many days,'" he remembered. "We just go up, knock the fire down and go back home."
Singleton didn't realize the enormity of the situation in lower Manhattan. When he arrived on the scene, the south tower had collapsed, though he didn't know that at the time. The area was a ghost town — littered with dust, shoes, purses and other debris. Singleton got to work right away, helping to man fire hydrants and extinguish fires around the perimeter of the building.
"We heard this loud bang, like something let go."
"Instinct told us that the (north) tower was coming down. So we ran. And it was every man for himself," Singleton recalled. The rest is a blur: He remembers getting about 30 feet from the building and falling. He dislocated his shoulder.
"I was on my hands and knees and I was waiting to die," he said. When he came to, he relied on his training as a firefighter to pull himself out of the rubble and debris. Covered in dust, he somehow made his way to the emergency medical services.
"I felt as if ... I wasn't really doing the job that I came to do," Singleton recalled about being injured while trying to help. After a doctor in the emergency room reset his shoulder, he returned to the scene to help as much as he could.
When he returned home later that night, his emotions began to set in.
"I felt angry ... I just couldn't imagine how a tragedy like this could have taken place in America," he said. "I fought in Vietnam as a Marine. ... There's no comparison to me. Because when tragedy happens at home ... the wounds cut deeper."
"I couldn't get outta bed."
"For a couple of weeks after the collapse, I actually wasn't sure if I was dead or alive," Singleton said. He frequently asked friends if he was alive. He couldn't do much and remembers just staring at the TV screen.
Eventually, he sought help for what he thought was depression. Singleton went to therapy at the Veterans Affairs facility in Brooklyn for about 10 months. The World Trade Center collapse had exacerbated the post-traumatic stress disorder he suffered after Vietnam.
Therapy, combined with his renewed spirituality, helped him get back on his feet. Today, he reads spiritual literature regularly and has found that talking about his experiences helps him work through the emotions.
He has dedicated a room in his home to 9/11 and FDNY memories. One wall is covered with photos from his time as a firefighter. Many of the men in the photos died on 9/11. He smiles looking at the pictures and recounts stories from back in the day.
"These guys would do anything for you," he said. "To rescue you, they would do anything."
He finds comfort in the photos and seeing their names at the 9/11 memorial.
"When people stop remembering us, that's when we truly perish," Singleton said. "I think as long as we keep the memories in the forefront, it keeps the people alive."
What 9/11 is like today
After 2001, living in New York City was difficult for Singleton. He struggled taking the train into Manhattan; when he looked to where the towers once stood, he saw all of the friends and co-workers he had lost.
"I would envision them falling through the rubble," he said.
Moving to Virginia offered a more peaceful lifestyle — and led him to find love. Soon after moving to Virginia, he met Mary Jean Hayres. On one of their early dates, he asked her when her birthday was, and she was nervous to tell him: It was Sept. 11.
Singleton was always forthcoming about his experience and his struggles with PTSD and depression, and "she understands," he said. "She supports me totally."
When the couple became engaged, they both decided to individually pray for a wedding date. When they regrouped, they blurted out the same date: Sept. 11. They were married at 11 a.m. on Sept. 11, 2012. While it's still a difficult day for Singleton, the couple now has something to celebrate.
Singleton offered advice for others going through difficult times: "Don't give up. Keep trudging ahead. ... It's all worth it."