Naxxramas is a giant necropolis floating over Stratholme, in Eastern Plaguelands. It has the honor to serve as the seat of one of the Lich King’s most powerful officers, the dreaded lich Kel’Thuzad.
In Classic WoW, Naxxramas is available starting Phase 6.
The instance consists of four different wings which, when cleared, grant access to the Frostwyrm Lair (a fifth and final wing). The first four wings are, in order of ascending difficulty: Spider, Plague, Deathknight & Abomination. Progression is non-linear – raids may select their own path to the final lair.