Destroyed German Flakpanzer IV "Wirbelwind". A destroyed Nazi anti-aircraft gun. These were based on the Panzer IV tank. Basically, the Panzer's turret was removed and replaced with an open-top, nine-sided turret which housed a quadruple 2 cm Flakvierling 38 L/112.5. Apparently, there were less than a hundred of these things produced during the war.