"We must be ready to dare all for our country. For history does not long entrust the care of freedom to the weak or the timid. We must acquire proficiency in defense and display stamina in purpose." - President Eisenhower, First Inaugural Address
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