June 2011, a Swedish diving team who were treasure hunting on the floor of the Baltic sea discovered something startling. A sonar image taken by Peter Lindberg depicted a UFO like structure on the sea bed. The team noted the unusual featured that appeared to be non-natural in origin. The team was searching for an old lost shipwreck. They noted that the sonar image was blurry but shows a sixty-meter diameter circular shape with ramps, stairways, and other structures that nature does not produce. Then the following year, in 2012, the team decided to return to the location where the image was taken but they claimed "mysterious electrical interference" prevented them from taking a clearer photo of the anomaly.  

The location of the anomaly is marked by the red circle above. Tabloids and other mainstream media were quick to claim it was a UFO that had crashed and skidded along the sea bed. Others pointed out the resemblance of the object to the Millenium Falcon. These claims have been largely debunked. Samples of the rock from the object were tested in Stockholm University by a Professor of Geology. The tests concluded that the structure was made of mostly granite, sandstone, gneisses and basalt. The rock was dated to be around 14,000 years old. Some have theorized that the structure was created by an ancient lost civilization but not enough evidence has been provided for a definite conclusion.

The rock may not be a UFO or an ancient structure but it is Very peculiar. The object lies 90 meters below the surface. Usually, when objects are at the bottom of the sea they get covered in silt over time, it appears that this hasn't happened. The object is disc shaped and has straight edges which are incredibly unusual, if not straight up impossible, in nature. 

No one yet knows for definite what the Baltic sea anomaly is and until the team behind its discovery (or another team who steps up) can provide more detailed footage of the object, we will never know what this UFO, ancient monument or freak of nature is.