http://www.leaderu.com/theology/palacedavid.html 
Part of the fortifications of the citadel, next to which King David built his palace. (2Samuel 5:9, 2Samuel 5:11) It was in this same palace that, "David got up from his bed and walked around on the roof of the palace. From the roof he saw a woman bathing. The woman was very beautiful... [and her name was] Bathsheba..." (2Samuel 11:2, NIV)