A headline would have readers believe that a ship discovered at the bottom of Lake Ontario by the Coast Guard is a German submarine, but this is fake news that has circulated for years.

"USA: Mysterious Nazi submarine from WWII discovered in Great Lakes," said a May 22 headline on Cvikas. A similar story has appeared on various websites since 2016.

Facebook flagged this story as part of its efforts to combat false news and misinformation on Facebook's News Feed. You can read more about our partnership with Facebook here.

The story said that amateur scuba divers first spotted the boat in January and contacted authorities. Then, the story went, archaeologists associated with Niagara University and master divers from the U.S Coast Guard determined that they were dealing with a German submarine that sank during World War II and recovered it.

But we found no legitimate news articles stating that such a sunken ship was recently discovered.

The story included a photo of a rusted submarine. Snopes found in 2016 that the photo was an unrelated image of a rusting, decommissioned Russian submarine from the Cold War era.

The story quoted Mark Carpenter, a supposed professor at the Niagara University. Thomas Burns, a spokesman for the university, said they do not have a professor by that name.

The Coast Guard told PolitiFact that the story about a recent discovery of a Nazi submarine in the Great Lakes is false. However, something similar has happened in the past.

"Years ago the Navy brought a WWII submarine onto the Great Lakes and at some point sank the submarine. So there is a WWII submarine sunken in the Great Lakes, but the Coast Guard didn’t work with Niagara University to recover a sunken WWII German submarine," the Coast Guard said in a statement.

ABC 7 Eyewitness News in Chicago reported in 2013 about the history of a sunken German submarine in Lake Michigan.

The German mine-laying sub U-C 97 was brought to the midwest on tour in the summer of 1919.

"The U-Boat was on tour. It was kind of a post-war, 'we won' tour, and so people got to go on to it and see it, and then as a condition of the armistice, it had to be sunk," Pritzker Military Library CEO Ken Clarke told ABC news.

In June of 1921, the sub was sunk by the military.

But in this case, the story declaring that a mysterious Nazi submarine from WWII was discovered in Great Lakes is made up. We rate this statement Pants on Fire.