Apocalypses in Fantasy Worlds

[drothgery]

Heck, Bujold's Sharing Knife series (which is essentially a romance in a fantasy setting, and hence I wouldn't be reading it if LMB weren't such a great writer) is post-apocolyptic.

Brust's Drageara after the Interregum (which is to say all of the Vlad books and all but the first two Khaavren books) is arguably post-apocolyptic (since at least for the Dragearan Empire, Adron's disaster was something quite close the apocolypse).

 

[Tonguez]

Conans Hyperborea is set after the fall of Atlantis - if that counts

Armageddon's Children details the quest of two Knights of the Word in protecting two powerful magics in a post-apocalyptic Earth. These are the Great Wars referred to in the Shanarra series which occurs centuries later

 

[Frostmarrow]

If you just need an excuse to end the world:

Exit Mundi

 

[Staffan]

The Land (from Stephen Donaldson's novels) had the Ritual of Desecration in the distant past, and in the second series pretty much had the apocalypse going on Right Now.

The Narnia books go from the creation of the world in The Magician's Nephew to its destruction in The Last Battle.

Many RPG settings have had great destruction in their past. Forgotten Realms had the Fall of Netheril and has the Spellplague coming up. Dragonlance had the Cataclysm. Barsaive (the Earthdawn setting) had the Scourge, which is still in living memory of the older-lived races. The Swedish setting Ereb Altor had the Third Conflux, where the Rome equivalent was eaten by hordes of insects (and had a series of adventures placed there called The Fifth Conflux - clearly the Fourth didn't leave much of an impression on the relevant area of the setting). Dark Sun had the Brown Tide and the Cleansing Wars.

For some smaller-scale acts of destruction, you have the Fall of Numenor in Middle-Earth, and Torak breaking the continent in half in the Belgariad backstory.

 

[Starman]

Final Fantasy VI has a pretty cool apocalypse half-way through the game.