this was the name given to the immense structure which served as the seat of power of the Yuuzhan Vong' Supreme Overlord, Shimrra, after the alien invaders captured and reformed the planet Coruscant. The Citadel was, in actuality, an immense worldship which had been constructed in such a way as to land in a specialized receiver that connected it to the planet's surface. Since the Citadel was mobile, Shimrra could move across the planet's surface without ever having to leave its confines. The Citadel's primary location was situated in the Well of the World Brain, on what used to be the most populous sectors of Coruscant. When on the ground, the Citadel rose from a yorik coral base and was virtually impregnable. However, should the need for escape arise, the entire bulk of The Citadel could disengage itself from the Well of the World brain and flee into space.