As he walked through the rubble where the Twin Towers had stood and fallen, Chicago firefighter Pat Maloney saw a tattered photo of a young child on the ground. Maloney wondered if that photo had been on the desk of a parent in an office — and if the child had been left without a mom or dad after the terrorist attacks of Sept. 11, 2001.

A parent himself, emotion overtook him as the reality of Ground Zero set in. It was a reality experienced by his two brothers, who also went to New York after the attack.

Almost two decades after the tragedy, nearly everyone remembers where they were when the planes crashed into the World Trade Center and caused the towers to collapse — the unspeakable horrors caused, the lives lost, the sobering impact on the nation.

But what do those who rushed to the scene in Manhattan in the immediate aftermath of the tragedy — the first responders — remember? What can they not forget 17 years later?

For Maloney, one of his most vivid memories is of that photo — which represents the thousands of people who weren’t as fortunate as he was to be able to later sit down for dinner with his four children and wife weeks after the attacks. As one of the legions of emergency responders from across the country who went to New York City, Maloney — at his home Tuesday in the Wildwood neighborhood on the Northwest Side — recalled seeing up close the destruction caused at a level the country hadn’t seen before.

“I remember coming across the George Washington Bridge and just seeing the smoke bellow,” said Maloney, who is now 57 and a battalion chief with CFD. “I mean we saw that on TV and then all of a sudden it’s a gut-check because now it’s real.”

Other memories — such as the smell — he would prefer not to talk about.

“Seeing a car still burning,” he said. “I was like, ‘How can that car still be burning?’ ”

He and a group of CFD firefighters worked around the clock in their 10 days in New York. At first, they slept on a sidewalk before moving into a nearby school.

“Every time you go to sleep, you think about someone gasping for air and you want to get back in there,” Maloney said.

Pat Maloney (left) and fellow Chicago firefighter Jim O’Donnell stand near the site of the 9/11 attacks in New York City. | Provided photo

Surrounded by trauma, Maloney knew he was where he needed to be, even if it wasn’t his city.

Still, it was two days into his time in New York that Maloney encountered a surprise. Near the command station where Chicago volunteers had set up camp, he saw his brother, Chicago Police Lt. Jim Maloney with a group of Chicago officers.

The two brothers didn’t know if they’d find each other in a city neither had visited before.

“I hugged Jim,” Pat Maloney recalled, “and I told him, ‘You’re not going to believe what you’re going to see here.’ ”

Chicago Fire Department Battalion Chief Pat Maloney shows an image of himself and fellow first responders at the scene of the 9/11 attacks 17 years ago. | Colin Boyle/Sun-Times

The two didn’t find out until they were back in Chicago that their other brother, Tom Maloney, also a Chicago firefighter, had also gone to New York to help.

“It was surreal,” Jim Maloney, who is now retired, said Tuesday. “We’re from Chicago and here we are in New York, and the enormity hit me.”

Jim, now 64 years old and the oldest of the three brothers, was aching to help as soon as he watched the attack on a television in his Northwest Side police district. When he learned a group of CPD officers planned to take a church-donated bus and drive to New York City, he knew he had to join.

One of the officers’ first jobs was to direct traffic in Manhattan.

“We’re wearing CPD uniforms in Midtown directing traffic,” Jim Maloney said. “We didn’t know where to send people, but they were coming up giving us hugs. They were happy to see us help.”

The officers searched buildings near the World Trade Center for days.

“All this dust,” Jim said. “There’s just so much — 6, 8, 10 inches of dust — that was just everywhere.”

Sometimes alarms would go off, warning of an imminent building collapse. But the risk to their own health wasn’t on the responders’ minds, Jim and Pat said. It was part of the job, just as it was back home.

In the years since, Pat and Jim have gone back to New York City — most recently two years ago — for ceremonies and memorial services. Tom has organized a motorcycle ride to New York for Chicago firefighters honoring the memory of their fallen members.

But, to this day, the three brothers haven’t all sat down together to discuss what they experienced in New York. They don’t block out the memories — they just haven’t talked about them.

“It’s like when you have an anniversary of the death of a loved one,” Pat Maloney said. “Your life continues, but you think about it.”