Greek Fire and the Silent Death of the A-bomb.

Greek Fire was the most formidable naval and siege weapon in Byzantine, and, likely, pre-modern, history.

It could burn on (or even under) water, lighting whole ships afire, and its composition was a closely guarded secret (indeed, even today, there is debate over its composition.)

How does such a weapon get lost to history? It is incredible that such a military advantage would not again appear until the Great War with the modern flamethrower.

The atomic bomb and its more impressive progeny may well be headed for the same fate. Now, I know, I know, there are plenty of parties interested in proliferating nuclear weapons from now until Judgment Day (perhaps even to hasten it) but culturally, we've moved on: the days of the Cuban Missle Crisis, the Midnight Clock...even Godzilla movies are now a part of an almost quaint history.

Perhaps a weapon that is so devastating that it has only been used once (well, twice) since its invention creates its obsolescence through its very power. Or perhaps it will lay latent for decades or centuries, awaiting its revival.

Just like Greek Fire.