The ships dotting the horizon wait days at a time to traverse the famous Panama Canal.
After taking about 50 photos of the sunset from the upper deck of the ferry I went inside to have a quick drink of water and liked the effect. Focusing was a pain in the butt (pro tip: disable autofocus and use manual instead ... much easier. :)
The ships you see on the horizon are lined up for the Panama Canal which is just outside of the left hand side of the frame.