The American flag seen in the iconic photo of the firefighters at ground zero on 9/11, which mysteriously went missing only hours after it was raised, has been found and will be displayed in a museum forevermore.

Thomas E. Franklin, the photojournalist who took the photo for The Record newspaper, had heard a few years ago that the flag had gone missing but did not know what to make of the mystery.

"I thought that was odd and unfortunate," Franklin told Metro on Wednesday. He said he is glad for the people for whom it has special meaning that it's was found. 

The flag will be put in a prominent display next to a print of Franklin's famous photo. 

"I'm honored that the flag will be displayed next to my picture," he said, adding that he thinks its appropriate home is the National September 11 Museum and Memorial, which does "an especially good job of telling the story of a really painful history, explaining it in a meaningful way."

FLAG RESURFACES IN WASHINGTON STATE IN 2014

When Franklin took the photo on the day of the terrorist attacks, the firefighters — Billy Eisengrein, George Johnson and Dan McWilliams — had removed the flag and its pole from a yacht named Star of America which was docked in the Hudson River near ground zero. Franklin captured the poignant flag-raising moment which was reminiscent of the image of American soldiers raising the flag at the battle of Iwo Gima in 1945.

After its short stint flying at ground zero, a flag, allegedly the original one, was unfurled at Yankee Stadium in 2002 and signed by Gov. George Patakai and mayors Rudolph W. Giuliani and Michael Bloomberg. But that flag was a replacement.

A grainy surveillance video featured on the pilot episode of Brad Meltzer’s "Lost History" shows that the original “9/11 flag” went missing hours after it was raised at the site.

A few days after the episode aired in 2014, a man calling himself “Brian” walked into a fire station in Everett, Washington, with a plastic bag saying he believed he had the flag, reported The New York Times.

Brian’s story was that he was a Marine deployed in the Middle East and was given the flag by a worker at the National Oceanic and Atmospheric Administration, who had been given the flag by the widow of a 9/11 victim. Experts (who will appear on a History Channel special about the rediscovery of the flag this Sunday) are dubious that Brian’s story is the whole truth.

The flag’s original owner also determined that a recently recovered one must be the original. Apparently, the flag taken from the yacht and flown on 9/11 was 3 feet by 5 feet, and the one signed by Giuliani was 5 feet by 8 feet, the flag’s original owners told the Times.

The forensic experts compared the dust on the returned flag to samples from ground zero, and found the same “fingerprint” of concrete, glass fibers, plastic, molten metal and asbestos.

Shirley Dreifus, who had owned the Star of America yacht from where the 9/11 flag was taken, has donated it to the Sept. 11 museum.

Though happy about the unlikely flag rescue, Dreifus told the Times she was saddened that her husband, who died two years ago, was not here to see the flag returned. “He called it the icon of the century,” she said. “This was the only symbol of hope that day.”