10 Times Humanity Found the Answer (and Then Forgot)

Greek Fire
In this 12th-century manuscript, the Byzantine navy fights an enemy vessel with 'Greek Fire' circa 900 C.E. Hulton Archive/Getty Images

In the ancient world, the ultimate expression of fire as a weapon of terror and ruin was a near-unquenchable "napalm" called Greek fire — a substance so legendary in its effects that "Game of Thrones" used a fictional version to decisive effect in its own epic (though fictional) Battle of the Blackwater.

In truth, the term "Greek fire" pops up all through history to describe several ancient and medieval substances combining various elements. Early versions used pitch, naphtha or sulfur, while Crusaders later faced Greek fire made with saltpeter and turpentine.

But for the real deal, scholars focus on a certain event that took place in seventh-century Constantinople (that's modern Istanbul, in case you don't know the They Might Be Giants song). There, in the year 673, true Greek fire — petroleum-based, self-lighting and impervious to water quenching — was said to have been used to devastating effect by Byzantine emperor Constantine IV's forces against an attacking Arab fleet. Sources claim the Greek ships launched the fire in pots or spat from tubes, possibly powered by Roman pumps [sources: Beschizza, Encyclopedia Britannica, National Geographic Channel].

Some have argued that the true Greek fire, invented by Callinicus of Heliopolis, a Jewish refugee from Syria, was already lost by then, and that the Constantinople formula was a weak imitation [source: Beschizza]. Oh, well — that's the problem with taking state secrets to your grave. Although we think we know Greek fire's basic fixings, the method of putting the stuff together remains a mystery — a reminder that, as with chemistry and baking, knowing the recipe is not always enough [sources: Encyclopedia Britannica, National Geographic Channel].