LAS VEGAS (KLAS) — Twenty years after the attacks of Sept. 11, 2001, thousands of T-shirts, hats, patches, pictures, and letters left at Las Vegas’ version of New York City are stored safely at UNLV.

“I believe it’s about 400 boxes, 5,000 shirts,” Peter Michel, of the Special Collections & Archives Technical Services department at UNLV said. Michel is the keeper of the collection of cotton.

Michel worked with his colleagues to catalog and save these individual memories of one of America’s darkest days.

“We document history in whatever way we possibly can,” he said.

A memorial to the victims of that day sat outside of the New York-New York Hotel & Casino for more than a decade, starting in September 2001.

Over the years, the casino worked with historians at UNLV to preserve it. The last part of the memorial remained outside until 2013 when a new promenade was built. A plaque now marks the site.

“If you were a fireman visiting in Las Vegas, you would have had this T-shirt,” Michel said about the plethora of T-shirts in the collection, each with its own department logo and design. With time, tourists across the country began bringing shirts and other items from their hometowns.

Twenty years after the attacks of Sept. 11, 2001, thousands of T-shirts, hats, patches, pictures and letters left at Las Vegas’ version of New York City are stored safely at UNLV. (KLAS)

“When you actually hold up a T-Shirt, you actually realize someone was wearing that T-shirt,” Michel said. “That belonged to an individual fireman somewhere who also puts his life in danger every day.”

More than 400 New York City first responders died in the terror attack.

Two decades later, the items in the collection remain unwashed and untouched but stored in hundreds of boxes at the university’s Lied Library.

Twenty years after the attacks of Sept. 11, 2001, thousands of T-shirts, hats, patches, pictures and letters left at Las Vegas’ version of New York City are stored safely at UNLV. (KLAS)

Opening the packages show just a glimpse of how we grieved in hopes future generations learn from our past.

“This is a moment in history,” Michel said. “This is a physical artifact of a moment in history that I think has to be preserved.”