One world, three campaigns
This world encompasses three different campaigns. The first campaign (D&D 2nd edition) ran from about 1996 to 1997 and ended in a typical Deck-of-Many-Things-climax. After an intermediate series of short adventures, a new campaign based on the Night Below boxed set was initiated around 1998 (maybe 1999). It started out using 2nd edition rules, but was converted to 3rd edition in 2000. The converted characters reached level 10, but were sadly annihilated in their first major fight against Inzeldrin, a green dragon. After that, the current campaign was launched late 2000, using 3rd edition rules. The new world-map incorporated the first (1996-1997) campaign setting, the Night Below areas and many new places. When 3.5E came out the campaign was updated, but apart from that it has been active continuously from 2000 up to now.