The Citadel, originally known as The Citadel of Ricks, was a trans-dimensional citadel city-state inhabited entirely by Ricks and Mortys from across infinite realities. The Citadel was originally located in an unknown dimension, but it was teleported by Rick C-137 directly to the main prison of the Galactic Federation from Dimension C-131 in "The Rickshank Rickdemption", which caused both buildings to collapse.