The problem is, they're not exactly sure what it is they've uncovered.
Out searching for shipwrecks at a secret location between Sweden and Finland, the deep-sea salvage company Ocean Explorer captured an incredible image more than 80 meters below the water's surface.
At first glance, team leader and commercial diver Peter Lindberg joked that his crew had just discovered an unidentified flying object, or UFO.
"I have been doing this for nearly 20 years so I have a seen a few objects on the bottom, but nothing like this," said Lindberg.
"We had been out for nine days and we were quite tired and we were on our way home, but we made a final run with a sonar fish and suddenly this thing turned up," he continued.
Using side-scan sonar, the team found a 60-meter diameter cylinder-shaped object, with a rigid tail 400 meters long...