"Unearthed by a group of sub-water explorers in 2011, a 60-meter-wide unique entity with a vast disc, twice the size of a football field, rests deep under the freezing waters of the Gulf of Botnia in the Baltic Sea region.
This Baltic sea anomaly is an unprecedented finding. The aura of mystery surrounding its background has popularly led to it being referred to as the Baltic Sea Mystery and the Baltic Sea Mystery Object."
https://www.marineinsight.com/maritime-history/the-baltic-sea-mystery-of-the-strange-ufo-object/
"In the annals of unexplained mysteries, the Baltic Sea Anomaly is one of the more bizarre deep-sea finds of the past decade. The discovery occurred in 2011 when a deep sea exploration team called Ocean-X, came across an unusual formation 300 ft. below the surface, off the coast of Sweden.
Upon further inspection, divers and surface crew reported malfunctions in their electrical equipment whenever they came within 200m of the object, which appeared to be shaped, oddly enough, like the Millennium Falcon from Star Wars.
Peter Lindberg and Dennis Åsberg came across the giant 180 ft. diameter mass on June 19, 2011, while trolling the Baltic and observing sonar imaging along the seafloor. They quickly picked up on the anomaly due to its circular shape and distinctively straight protrusions. Adding to the mystery was what appeared to be an extensive trail – what some speculated could be evidence that a crash landing may have taken place."
https://www.gaia.com/article/the-baltic-sea-anomaly-a-crashed-ufo-or-natural-rock-formation
UFO Found In Baltic Sea circular object