There's a helmet and two water bottles on the top of the tank, which indicates the true scale of the photoshopped tank.

In addition, I'm guessing that few of you are familiar with metric measurements. A 478 mm gun has a bore of 47.8 cm, which converts to almost 19 inches. Just for fun, do a search for 19-inch guns, and see how many warships had them.

At first glance, I was almost fooled, too.