Finally, a closer view of the USS Iowa's Mk.15 Phalanx AA Gun!

The Iowa class Battleships are notable for being the only warships in history to mount FOUR of these guns, giving them some of the best air defenses seen before or since (though their range is a bit wanting, compared to missiles and the Iowa's considerable 5in gun battery).

I later photo will show you a close-up of the weapon, and I'll give you a few more technical details.

Have a look at a video of the Phalanx in action, to appreciate how powerful it is;
http://www.youtube.com/watch?v=T4hA8IqSC58

Here's some information on the Phalanx, for those interested;
http://www.navweaps.com/Weapons/WNUS_Phalanx.htm