Location: Milky Way / Serpent Nebula / Widow
Supposedly constructed by the long-extinct Protheans, this colossal deep-space station serves as the capital of the Citadel Council. Gravity is simulated through rotation, and is a comfortable 1.02 standard G's on the Wards and a light 0.3 standard G's on the Presidium Ring.
Total Length (Open): 44.7km
Diameter (Open): 12.8km
Population: 20.3 million
Gross Weight: 7.11 billion metric tons
Crucible and CatalystOlivia Shepard, and Alistair Creed's possession.
Unfortunately, the Illusive Man learns of this and flees to the Citadel, where he alerts the Reapers of the galaxy's plans. The Reapers respond by seizing control of the Citadel and moving it into Earth's orbit to protect it. The station's arms are closed, sealing it off, thereby preventing the Crucible from docking. The Alliance leaders determine that the only way to get the Citadel's arms to open is to get someone inside the Citadel and manually open the arms.Earth, Commander Shepard, Olivia, and Alistair board the Citadel via a transport beam and opens the Wards to allow the Crucible to attach to the station. Shortly afterward Shepard, Olivia, and Alistair are confronted by the Reaper AI and in an attempt to thwart their advances, becomes each one of their deepest fears and regrets to lessen their fortitude. For Commander Shepard it was Saren; for Olivia it was her Mother; and for Alistair it was his protege, Jared Kaine. After a lengthy battle of wits and of guns, they manage to activate the fail safe that destroys the Reapers, as well as the Reaper AI, and leaves everything else intact.
The Citadel is a massive construct, similar in shape to a pentagram. It consists of a central ring 7.2 kilometers in diameter, from which five arms protrude, each 43.6 km long and 330m thick.
The station is capable of closing in on itself, via the convergence of its five arms, transforming it into a long, impenetrable cylinder. However, the Citadel is only closed in times of emergency, and normally the station retains its 'open' appearance.
The central ring and five arms are home to the Presidium and Wards respectively; the Spaceports and Docks are also located on the central ring, as it is the center of rotation, facilitating easier access for ships attempting to dock with the station.
The Citadel has a labyrinthine interior superstructure, once accessible through keeper tunnels and now mostly sealed off.
PresidiumPresidium is a massive, park-like complex containing the offices and residences of the various branches of the galactic government, as well as the embassies of all the races represented in the Citadel. There are also shops, restaurants and recreational facilities, serving the wealthy residents who live and work throughout the sector. The Presidium is monitored by a Virtual Intelligence named Avina, and, unlike the Wards, incorporates an artificial 20-hour day schedule: lights are dimmed, and the holographic "sky" darkened, for 6 of the 20 hours, imitating the familiar day-night cycle.
The famed club Guilty Pleasures is located in the old Purgatory location, and serves as the Presidium's premium locale, including Apollo's Cafe, and the Boardwalk (A locale with a row of high end shops).
The tower at the center of the Presidium houses the Council Chambers and the main traffic control for the station—any ship within a few thousand kilometers comes under the jurisdiction of Citadel Control. The Chambers themselves are not open to the public and access is only granted to officials and those with special clearance. They are beautifully furnished, with cherry trees and fountains, as well as numerous staircases leading up to the central platform where the Council convenes.
WardsWards, constitute the residential and commercial sectors of the station. Densely populated, housing millions of residents from many galactic species, the Wards are akin to Earth cities such as Hong Kong and Singapore.
Numerous skyscrapers rise from the superstructure, sealed against vacuum, as breathable atmosphere is only maintained to a height of approximately 7 meters. Unlike the Presidium, there is no artificial day-night cycle; as a consequence of this, commercial activity rarely ceases, and residents work and rest according to personal need. Olo Shan appropriately dubs the area the cultural heart of the Citadel, and therefore of Citadel space.
The Wards are policed by the Citadel Security Services (C-Sec), whose offices and custody suites are located in the Lower Wards. The Last Resort is a popular and laid back club, located in Shin Akiba, and owned by Veralia Shepard. The Wards are also home to the Silversun Strip, a busting commercial and residential area featuring the Silver Coast Casino, Castle Arcade, Armax Arsenal Arena, and the twin blue and white condo complex Creed Towers . Below the Wards, the Citadel Archives function as a repository for the artifacts and records deemed important.
Another link in the Citadel's defensive chain is the Citadel Fleet. The fleet is a massive task force consisting mostly of human and turian vessels but also including ships from the other Council races. The Citadel Fleet, led by the imposing asari dreadnought Destiny Ascension, constantly patrols the space around the station. However, should any aggressor manage to break through the Citadel Fleet, reinforcements from all over the galaxy are only minutes away, due to the network of mass relays located nearby.
If any enemy gets close enough, the station is capable of closing in on itself to form a long, armored cylinder, 45 kilometers in length. The station's hull is sufficiently strong that, even when subjected to the most advanced weaponry available, it would take several days of sustained bombardment to inflict any serious damage to the superstructure.
The station also boasts its own internal security force, known as C-Sec. The 400,000 officers patrolling the station handle everything from customs to hostage negotiations.
The Citadel also has turrets to ward off small craft, such as dropships.