This is pretty cool, it is one of only a couple of coastal defense shield guns still in existence. The gun is located at Fort Pickens National Park, an area continuously used as a coastal defense location from 1830 until after WWII. Shield guns guns date from the WWII era with this gun a 6 inch caliber (X aprox 40) with a range of 27,000 yards. There are 2 mounts like this with the other being about 50 yards away. Each gun had a crew of 25, housed and equipped in a reinforced concrete bunker below the mound visible in the background on the right of the bottom picture.