In the struggle for control over this key real estate, countless mines were planted, and naval warfare waged to protect key shipping routes, especially for the Germans who relied on a supply of iron ore imported from Sweden. Needless to say, it was an epicenter of naval activity, primarily in the battle to control the Baltic states of Lithuania, Estonia, and Latvia.

Less than five percent of the planetвЂ™s oceans and seas have been explored, and though the Baltic is almost entirely landlocked, it is a massive body of water located in what was a hotly contested area during WWII.ДЄt that time, the Baltic Sea created a natural boundary between the Allied Soviet Union, neutral Scandinavia, and the Axis powers of the Third Reich. вЂњMy hypothesis is that this object, this structure was formed during the Ice Age many thousands of years ago.вЂќ вЂњI was surprised, when I researched the material I found a great black stone that could be a volcanic rock,вЂќ BrГјchert said. The crew returned to the surface with samples of the object that were later tested by Volker BrГјchert, an associate professor of geology at Stockholm University. The explorers pointed to what appeared to be a staircase and a rounded hole encircled by a square frame as what they believed were distinctively artificial features. Looking at sonar imaging, the anomaly showed interesting characteristics that seemed to distinguish it from a natural rock formation. This allowed them to embark on the bold endeavor of investigating the Baltic anomaly, which they hoped was either an extraterrestrial spaceship or a secret Nazi structure from WWII. The two parlayed their clout from a previous exploration, in which they recovered a cache of vintage champagne from a 1907 shipwreck that sold for record prices at a ChristieвЂ™s auction. Shortly after their discovery, Lindberg and Г…sberg set out to create a documentary that chronicled their attempts to dive down and study the anomaly.

Baltic sea anomaly