Tiberian Spiral

The Tiberian spiral galaxy, known as the "hibernation galaxy", (PROSE: The Mondas Touch) was a galaxy associated with the Cybermen. (TV: Nightmare in Silver)

The Cyber Legions were active in the Tiberian Spiral. The Ninth and Eleventh Cyber Legions once joined forces to conquer the planet Agrippina in the Tiberian Spiral. The Cybermen were ultimately successful, with the human colonists of Agrippina having only antiquated anti-cyber guns to defend themselves. (PROSE: Ghost in the Machine) The Fifth Doctor visited Agrippina during this time. (PROSE: A Girl Called Doubt)

The galaxy was destroyed in its entirety by a human empire in order to defeat a Cyberman army. At this time it contained, according to Porridge, "a million star systems, a hundred million worlds" and "a billion trillion people." After its destruction, nothing of the galaxy was left, just a black, gaping hole in space easily identified by an outwards swarming bluish "ring" around the general area. The destruction of the galaxy effectively wiped out almost all Cybermen in the known Universe, to the point that most believed them to be extinct. Unbeknownst to the human empire a small number of Cybermen survived and began rebuilding their forces on the planet Hedgewick's World of Wonders. (TV: Nightmare in Silver)