Plastic water tanks are a far cry from the armored behemoths also called tanks, but they do share a curious historical connection. Yes, that’s correct, modern plastics were invented after World War II, while tanks first made their debut in the waning years of the Great War, but there’s something of a relationship.

Although not plastic water tanks, military tanks were first so named by their British creators in an effort to disguise their research and development. It was hoped that by classifying these inventions simply as “tanks” on paper, any German spies who might have gotten a hold of the secret documents that referred to them could maybe be mislead. As it turned out, the label stuck and tanks have been called just that ever since.

In English, anyway. In German, and numerous other languages, they’re known as only “armor,” a more appropriate term which is a recognized synonym in the English-speaking world, particularly among military circles. A far cry from today’s plastic water tanks indeed, but the notion is never far away in the minds of military history buffs.

The connection is a little more than merely etymological, in fact, as the earliest designs did look like nothing more than basic water tanks to those who had the security clearance to see them. Tanks have dominated the battlefield for over sixty years, and even nowadays they form the core of most conventional land warfare tactics.

The introduction of attack helicopters and guided missiles have greatly reduced their striking power, as well as the asymmetrical warfare prevalent in conflicts nowadays render them ill-suited for most missions, but nothing on the horizon can match the tank in its useful combination of firepower, maneuverability, and defensive capacity. Though less used, the tank still figures eminently in invasion tactics and grand strategy and should find a role for itself in the decades yet to come.