Ten years after leaving the Sol system, humanity makes its first contact with an extraterrestrial species, the turians, which erupted into the First Contact War. Though casualties are small on both sides, the war is interrupted by the Citadel Council, members of three races that oversee peacekeeping in the galaxy. Humanity is then welcomed into the collective community of extraterrestrial species, and learn that the artifacts, mass relays, and the giant station that serves as the seat of power in the galaxy, the Citadel, are all that remains of the Protheans, believed to be the pre-eminent civilization in the Milky Way galaxy but have since disappeared tens of thousands of years ago. The Citadel Council welcomes humanity into the Citadel community, providing them with a Systems Alliance embassy and allowing individual members to join the Citadel Security Forces (C-Sec), despite other client species having waited for such a privilege for some time. The Citadel Council soon invites a human to join the Spectres, elite enforcers that use both espionage and force to complete their assignments.