|Powers and Abilities||Can shift its interior|
The Citadel is a large building in the center of Ultra City. It was built by Ultron and its robots to be its headquarters. There, it could monitor all that went on around it. It also housed Ultron's Trophy Room where it kept the remains of all the fallen heroes. The interiors could shift to suit Ultron's needs and the nearby towers could move towards and away the Citadel. Ultron captured Iron Man and kept him in the Citadel to lure the children of the Avengers to it. It worked and they fought Ultron and the Iron Avengers. The Scavengers snuck in and rescued them.