The world’s most mysterious underwater object just gave up a secret it kept for 140,000 years—and the truth is terrifying. Divers probing the Baltic Sea Anomaly, the massive disc-shaped structure that sparked endless alien theories, claimed it was just a glacial deposit.
In June 2011, marine surveyors Peter Lindberg and Dennis Asberg were mapping the northern Baltic Sea floor when sonar detected a large, circular object roughly 60 meters across. The shape had unusually sharp edges, and a straight, 300-meter trench extended from one side of it across the seabed. The discovery puzzled the team, which had years of experience locating shipwrecks and recovering cargo f…