It looks almost like a pearl necklace or that someone has tried to make a fireplace with an inch-sized rocks on the ocean floor.
The furnace-like rock formations on top of that which constitutes the large circle that was discovered with a scanner tool last year. Divers images shows that the circle in turn consist of several blocks formed by "rolls" or "mushrooms" that is attached to each other, forming the circle. Overall, the object is 60 meters long and about as wide.
Video is in Swedish, but there is an English translation transcribed in the "Show More" section