Before sunrise on Friday, firefighters from across the U.S. gathered at the Manitou Incline to walk the more than 2,700 steps in honor of the 343 New York City firefighters who lost their lives trying to save others in the immediate aftermath of the Sept. 11, 2001, terrorist attacks.

Some Manitou Springs and Colorado Springs firefighters showed up despite having just completed their shifts. Others had a shift to look forward to after the ascent.

Many were dressed in full turnout gear, making an exhausting climb even more difficult. Others had not yet been born when the attacks took place 25 years ago.

“We already have a generation of people – adults – who were either too young to remember 9/11, or weren’t even born,” said Mark Tonin, who drove in from Montana. “I’m glad some of them showed up today.”

Commemorative 9/11 stair climbs take place at venues across the U.S., and Tonin has attended several, but the Manitou Incline stands out for him.

“I’ve done stair climbs, but most of them involve going up a few flights of stairs, then coming back down and doing it over and over again,” he said. “This is the only one I could find that goes straight up. To me, that’s important, because it brings us closer to what those firefighters must have felt that day.”

After gathering at 6:30 a.m. for a brief memorial, the Fire Department sounded sirens at 6:46 a.m. to mark the time the plane hit the north tower of the World Trade Center.

Other alarms sounded as the group ascended the 2,000-foot climb to mark some of the other major events that day, including the plane hitting the south tower, American Flight 77 crashing into the Pentagon, United Airlines Flight 93 crashing into a field in Pennsylvania.

In the 25 years since 9/11, more than 600 firefighters have died of World Trade Center-related respiratory illness from breathing toxic smoke and dust in their search for survivors, according to the International Association of Fire Fighters. Their sacrifice should be remembered as well, Axel Solis said.

“I wasn’t born at the time, but it was a catastrophic event and a lot of lives were lost,” said Solis, 22. “It’s a hard climb. It kinda sucks. But it’s the least I can do.”

Derrick Self, a lieutenant with the Parker County Emergency Service District in Texas, was in grade school on the day of the attacks and remembers watching the horror play out in a continuous loop on television.

“This is a big anniversary for (firefighters),” said Self, who made the climb with his wife, Anna. “The reason a lot of people my age got into firefighting was 9/11.”

It was a somber, quiet event, but also one marked by fellowship and solidarity, said Kris Godwin, a Manitou volunteer firefighter.

“I’m not a professional firefighter, but a lot of my friends are, and I’m here to support them,” Godwin said. “This day is about remembrance, but it’s also about community and camaraderie.”

Self said he was impressed and encouraged by the hundreds of firefighters and well-wishers who showed up early Friday to honor their fallen brethren.

“This is a great turnout, and Manitou Springs has been really welcoming to us,” he said. “It’s a tough day. But it’s awesome to see how many people showed up.”