MAHWAH, N.J. (CBSNewYork) — It’s a mini-museum on wheels, a traveling Sept. 11 exhibit in a truck.

Its mission is simple: Never forget.

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Retired firefighter Richie Murray and retired Battalion Chief Jack Oehm volunteer by bringing the story of 9/11 across the country, WCBS 880’s Sean Adams reported.

“I want everybody to remember this day and never forget what happened,” Murray said. “So I bring it back to life, and I tell my stories so that you know what happened.”

“Out of of sight, out of mind,” Oehm said. “Well, we don’t want to be out of sight. We don’t want to be out of your mind. It’s so important.”

The 1,000-square-foot trailer features video, audio, artifacts, a twisted piece of World Trade Center steel and firefighter tools.

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“This is a shirt that one of the lieutenants, Lt. Dennis Ober, wore searching for his son, who was a fireman that got killed that day,” Oehm said.

Firefighter gear is seen inside the 9/11 Never Forget Mobile Exhibit. (Credit: Sean Adams/WCBS 880)

Firefighter gear is seen inside the 9/11 Never Forget Mobile Exhibit. (Credit: Sean Adams/WCBS 880)

The 9/11 Never Forget Exhibit is part of the Stephen Siller Tunnel To Towers Foundation. Every year, runners retrace Siller’s footsteps as the firefighter lugged 60 pounds of gear on his back and ran through the Brooklyn Battery Tunnel to reach the burning towers.

“9/11 was fourteen years ago, and there’s a lot of kids out there that didn’t experience it and understand what happened that day,” said Greg Siller, Stephen Siller’s nephew. “And this is to remind them what they went through and understand why our veterans are over fighting for our country, our freedom and coming home, and we’re trying to take care of those wounded warriors.”

The exhibit recently visited Greg Siller’s employer, Stryker Orthopaedics in Mahwah, New Jersey, where employees learned about the foundation’s mission of building special homes for disabled veterans.

“Their goal is to build 200 homes, and those aren’t cheap homes — they’re about $600,000 each to build because they’re custom homes, and they’ve built 56 so far,” Greg Siller said.

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For more information on the mobile exhibit, click here.