A city in Maine is trying to solve a huge mystery after a giant rubber duck appeared in its busy harbor. 

The 25-foot-tall duck -- which is emblazoned with the word "joy" -- appeared in the harbor in Belfast, Maine, on Saturday, according to the New England Cable News. No one knows who put it there. 

The station reported that the duck is anchored in shallow water between a pedestrian bridge and the town landing. 

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Harbor Master Katherine Given told the Bangor Daily News that the duck doesn’t pose a navigational hazard, so there's no rush to shoo it away.

A giant rubber duck appeared in the harbor in Belfast, Maine, on Saturday but residents still don’t know how it got there. (New England Cable News/Kenn Tompkins via AP)

A giant rubber duck appeared in the harbor in Belfast, Maine, on Saturday but residents still don’t know how it got there. (New England Cable News/Kenn Tompkins via AP)

"Everybody loves it," Given said. "I have no idea who owns it, but it kind of fits Belfast. A lot of people want to keep it here."

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Judy Herman, of Bala Cynwyd, Pennsylvania, stopped to snap photos on Tuesday.

"It’s wonderful," she told New England Cable News. "Who would expect to see a duck in the middle of the water here?"

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The Associated Press contributed to this report.