ROME — Retired New York City firefighter Robert Reeg will never forget his experience at Ground Zero on Sept. 11, 2001, when the World Trade Center was attacked by terrorists and came crashing down around him.

Stationed with FDNY Engine 44 on the Upper East Side of Manhattan, Reeg was on the ground getting gear from a truck when he looked up and saw the top floors of the South Tower explode. Reeg took off running as his world erupted.

“Girders were rocketing past us like they were shot out of a cannon,” Reeg said on Thursday as he shared his story at the 9/11 Never Forget Mobile Exhibit on the Griffiss Business and Technology Park in Rome.

Reeg was struck in the head and back, which pulverized his ribs, and he was buried in rubble. He said he was declared missing for most of the morning.

“It sounds weird; we were the fortunate ones,” Reeg said, referring to those who were only injured on that tragic day. A total of 343 firefighters died on Sept. 11, and more have died since due to 9/11-related illnesses.

Since then, Reeg has shared his story, and he was in Rome to attend the opening ceremony of the 9/11 Mobile Exhibit as it started a 4-day visit to the region. The exhibit — open from 10 a.m. to 4 p.m., is free and open to the public, and will be at the Griffiss Park through Sunday, April 23.

Like Reeg, other FDNY firefighters who served on Sept. 11, 2001 are on hand to serve as tour guides and share their stories at the exhibit.

“Without the love and support of all of America, I don’t know if we would have been able to bear the sorrow,” Reeg told the gathered crowd.

“The young people don’t even know what life prior to 9/11 was like. We need to make them aware.”

Along with the living tour guides, the exhibit features a timeline of the events of 9/11, including information on the 1993 attack on the World Trade Center — and Reeg was serving back then as well.

There are artifacts pulled from the debris, including metal from the towers. There’s a list of the lives lost, and several exhibits showing off gear and other mementos from the police officers and firefighters who gave their lives.

“It is extremely important that we remember the events of Sept. 11, 2001. We know exactly where we were, what we were doing, and we’ll never forget that,” said Rome Mayor Jacqueline M. Izzo, who was on hand to welcome the firefighters and military officers who attended the opening ceremony. Izzo recalled how the Eastern Air Defense Sector in Rome played a “pivotal role” on Sept. 11, including scrambling fighter jets as a response.

“It really does bring home something that no one here will ever forget,” said Oneida County Executive Anthony J. Picente Jr., who was also in attendance.

“Generations have been born that don’t really know. There are many things that we should never forget. Please encourage your friends, young people, people of all ages, to come here.”

The 9/11 Never Forget Mobile Exhibit was built and is maintained by the Tunnels to Towers Foundation, which also hosts 5K runs around the country in memory of FDNY Firefighter Stephen Siller. The Tunnel to Towers Central New York 5K Run & Walk in Utica is scheduled for August, and registration is now open.

The mobile exhibit is held inside a tractor trailer and tours the country. It was brought to Rome by the combined efforts of U.S. Army Staff Sergeant Matthew Squairs, who works recruitment in Rome, and AmeriCU Federal Credit Union. Squairs and representatives of AmeriCU were also on hand at the opening ceremony.

“It feels really good that everything is running smoothly now, and that we have a really good turnout, so I’m pretty happy with it,” said Squairs as he watched the first tour groups enter the exhibit.

“We’re very hopeful that a lot of people are going to come.”