Image is believed to be in the public domain.
Uploader comment: My daughter and I took a trip to Hearst Castle back in 2007. I was recently showing these pictures to my new sister in law and she asked "What is that" when I blew up the image it looks like it has small round windows like on a boat. I did not see this at the time I took the photo my eyes were focused on that splendid pool. What is this object?