The USS Iowa's Redwood deck has been stripped off of the forecastle (probably for maintenance), revealing interesting little details like this one.

This is where a 40mm Bofors AA gun was once mounted, along with a considerable cylindrical gunshield that surrounded it. They were literally welded to the deck, leaving behind shiny solder when the Navy removed them later with cutting torches.

Here's what the complete 40mm weapon system looked like in the Iowa's heyday --- look in the lower-right-hand corner of the photo;
http://navsource.org/archives/01/061/016107a.jpg