Explorers discovered the odd-shaped object on the ocean bed of the Baltic Sea in June 2011.
Dubbed the Baltic Sea Anomaly, the object is a 70-metre long (210 feet) strangely-shaped feature that showed up on sonar laying 100 metres (300 feet) beneath the waves.
Theories as to what the Anomaly could be have ranged from the interesting to the outrageous, with some claiming it could be part of fleet of crashed UFOs on ocean floor.
Some conspiracy theorists even point out it bears a striking resemblance to the Star Wars Millennium Falcon with a steel grey appearance.
Others have claimed it could be the remains of a sunken city lost to the waves years ago.
However, a group of divers collected samples from the mysterious entity and gave their finding to scientists who determined that the Baltic Sea Anomaly is simply a glacial deposit.
Much of the Baltic Sea was carved out by moving glaciers during the Ice Age.
Research undertaken by scientists from Stockholm University has revealed the Baltic Sea Anomaly is leftovers from that process.