Pff, that's nuffin. To end my 2e campaign before starting with 3e, I made a big adventure (Planescape/Dragonlance crossover) which involved a powerful Yugoloth scavenging five "nukes" - magical artefacts, really - and putting them to good use... when the adventure was over, a desert city in northern Ansalon had been vaporized; the PC's home town on the Outlands had been vaporized; Neraka was vaporized; Palanthas was vaporized; and noone knows where the fifth nuke went. Talk about going with a bang.