Guild Tower is a guildhall located above the Storage Cellar at the pinnacle of the structure in central Markarth. It houses the Mages and Fighters guilds. Achdazan practices archery on the targets out front, producing the sound of arrows being fired which you may hear in several parts of the city. When you enter the tower, you'll be met by a narrow, winding staircase that leads into the hall proper. The hall is full of shops. The Mages Guild quarters lie to the south. An advanced safebox is located against the eastern wall, next to a shelf. The Fighters Guild quarters are in the north. One guard walks back and forth between the guild sleeping quarters. Another guard is posted in the center of the market.
An advanced safebox can be found in the small storage room far to the west, all the way across the hallway at the bottom of the stairs.