Circles Appear in the sea in front of Croatian islands, Residents Fearful That Aliens Are The Cause, May 2014, UFO Sighting News.

Date of discovery: May 2014

Location of discovery: Croatian Islands

Source: http://www.likecroatia.com/news-tips/underwater-circles-ufos-adriatic/

Many unusual circles have appeared around the Croatian islands, causing the residents to worry. Some even say its aliens that cause it, because they often see circle formations in the sky above the location the circle are in the water. The circles are evenly spaced apart and are found around several islands. SCW

Like Croatia states: 

During last year’s routine underwater mapping, 28 perfect round shapes were discovered in the underwater vicinity of Dugi Otok Island. Each of them has 50 meters in length, and the circles are 300 meters away from each other. They consist of unexpectedly rough terrain, devoid of any floral life, as if some Godzilla-like being walked the Adriatic’s bottom, leaving its circular footsteps in the underwater grassland.

"At first we thought it was some sort of photo manipulation, so we dived at one of the locations, and sure enough, the circles were there. They had a perfect edge, as if someone pulled the Posidonia out with a corkscrew."

Possible Ancient Aliens Of Atlantis Found Near Island of Terceira, Sept 2013.

Location of discovery: Between Terceira and Sao Miguel islands. 

Date of discovery: Sept 2013

Source: Alton Parrish at http://beforeitsnews.com/beyond-science/2013/09/giant-underwater-pyramid-found-near-azores-island

Researchers have discovered an underwater pyramid 60 meters high and 8000 meters square base near the Bank De João de Castro, between the islands of Terceira and São Miguel. The structure was identified by the sailor Diocleciano Smith based on bathymetry readings. The author does not believe that the pyramid is of natural origin. The Government says that the matter is already being investigated with the support of the Portuguese Navy.

A person made a comment below the video on Youtube interpreting some of what was said in the video, he states:

Since there arent English subtitles here's somethings he said that are interesting:

-He says the vertexes of the pyramids are aligned in a way that one of them points north and one of them points south, exactly like the pyramid of Giza.

-H base bigger than a football stadium.

-He found it a few months ago but he couldnt really believe it, he kept it a secret and began to study it, he then decided to reveal it.

-The man already gave the coordenates to portuguese officials for further study.