Archaeologica.org

http://new.edp24.co.uk/content/features ... 3A52%3A897

Story of the seahenge in the UK. Be prepared to turn the sound off of the movie clip if you don't want to hear it.

What caught my eye about it is the fact that there is one almost identical to this in Florida, and half of it is in the ocean.

Yeah, it is called the Miami Circle. It sits on some of the most expensive real estate in the country.
You can Google it.
At first they called a Mayan or Olmec construction, but the local N A protest shot that down, so now it is supposed to be from the local tribe.
They base that on stuff found in and around it. No thought is given to the idea that a local, nomadic tribe might make use of a preexisting structure they found in a convent spot. And, that as nomads, they had no history or reason to build such a labor intensive place.