The Sky Fortress, not to be confused with the Sky Palace, is the current home and residence of the first Emperor, Jarethan I. Since his retirement he had the sky fortress constructed as his personal home. It is a grand construction, using the levitation methods that the Dalaran Mages used to rebuild their city, and float it to northrend.
The Sky Fortress features many of the similar imperial designs, utilizing massive stone walls like those found in Ulduar and Fortress Wintergrasp. The building is essentially a complex of halls, and towers, with a grand boulevard in the center leading to his main residence. Meeting halls and banquet halls full of tables and chairs, seating arrangements meant to maintain the Emperor's vast staff were built to accommodate them.