It is said this vast station was constructed by the long-extinct and near-mythical Protheans.
First discovered by the Asari soon after they learned how to use the Mass Relays, this colossal deep-space station serves as the capital of the Citadel Council.
The Asari were joined shortly by the Salarians, and soon after, the Volus. As other races were contacted by the Asari, or discovered the station independently, they gained embassies on the Citadel and came under the jurisdiction of the growing Council, eventually comprised of the Asari, the Salarians, and the Turians.
Strategically located at the junction of a number of mass relays leading to various parts of the galaxy, the Citadel quickly became a hub of activity. The station was chosen to house the Citadel Council, thereby cementing its importance in the galactic community. It is accepted to be the political and cultural heart of Citadel space, the unofficial name given to all systems that fall under the Citadel species’ control.
Total Length (Open): 44.7km
Diameter (Open): 12.8km
Population: 13.2 million (not including keepers)