"History does not long entrust the care of freedom to the weak or the timid" - Gen Eisenhower.
Using side-scan sonar, the team found a 60-meter diameter cylinder-shaped object, with a rigid tail 400 meters long.
Most of the Baltic is less than 300 feet deep, with a few spots that go down to about 600. Pretty easy to send an ROV or submersible down to take a look, or even sampling gear like bounce cameras, grabs or coring devices.I suspect it's just a current artifact or geological feature, another "face on Mars" deal.
My favorite hypothesis: http://memegenerator.net/instance/12426459