What is Naxxramas in World of Warcraft

Naxxramas (Naxx) is the introductory raid floating above Dragonblight in Northrend. It is in the style of a floating Scourge necropolis. Naxx was moved to Northrend by Arthas from its former home in the Eastern Plagulands and was originally a 40 man raid, but is now a 10/25 man raid. It also has a ton of bosses to grab loot from.