The Baltic Sea Anomaly — Sonar Reveals Geometric Object 90 Meters Below Surface

In June 2011, Swedish treasure hunters Peter Lindberg and Dennis Åsberg of Ocean X Team were searching the Baltic Sea floor when their side-scan sonar revealed an unusual circular object approximately 60 meters in diameter at a depth of 90 meters. The object appeared to have raised edges, a flat top, and a distinct path or runway leading to it.

A 2012 expedition returned to investigate with dive teams. Divers reported that the object appeared to be made of a solid material, and that electronic equipment—including underwater cameras and satellite phones—malfunctioned when within 200 meters of it. The malfunctions ceased immediately upon moving away from the object.

Samples from the object were analyzed and found to contain black material with an unusual composition including limonite and goethite. Geologists who examined the data were divided between those who attributed it to a natural formation—a glacial deposit—and those who considered the geometric regularity and equipment interference anomalous.

The object attracted enormous public interest when compared to the Millennium Falcon spacecraft from Star Wars. Ocean X team has conducted multiple follow-up expeditions. While most geologists consider it a naturally occurring structure, the consistent electronic interference reported by divers and the unusual geometry continue to be cited as unresolved elements of the case.