The Presidium is the gleaming heart of the Citadel Station. It is located in the 10km wide central ring of the station. It is home to the various government offices of the Citadel Council, as well as embassies for all of the species represented in the Citadel.
The interior of the Presidium is landscaped to resemble a lush parkland on a 'G' type planet (using the Systems Alliance's Morgan-Keenan classification system). No detail was overlooked, boasting a large freshwater lake, verdant fields of grass, trees, and clouds, as well as artificial sunlight and gentle breezes.
The buildings are built along the curving walls of the ring, and were meant to blend in unobtrusively with the surroundings. Located in the very heart of all this is the immense Council Tower, where the Citadel Council itself meets and holds audience with ambassadors from the various governments.