Baltic Sea Anomaly

A 60-meter disc on the seabed that, divers claimed, killed their electronics on approach.

2011: Swedish treasure hunters (Ocean X team) sonar-imaged a 60-meter circular formation with what they described as ramp and staircase features at 87 meters in the Baltic. Divers reported equipment malfunction near it; geologists who examined recovered samples identified glacial deposit stone. No peer-reviewed survey has settled it; the team's commercial framing invites skepticism. Filed in the USO cluster as the underwater analog of every blurry aerial case: a real sonar return wearing an unearned silhouette.