Doctor Who: 10 Times The Doctor Went To War

6. The Cyber Wars

The Cybermen have always waged war across the universe, conquering and enslaving planets. Convinced they are the superior species and need to 'upgrade' lesser lifeforms, these creatures exist as a constant threat to all life.

An early example of the silver giants' conquests is their invasion of Voga in 1975's Revenge of the Cybermen. More recently, the Thirteenth Doctor battled against a warrior-class primed for warfare. Under the control of the Master, these Cybermen invaded Gallifrey and upgraded its citizens - showing that even the mighty Time Lords are at risk from these unstoppable creatures.

A separate Cyber War was won by humanity in the Tiberian Spiral before the events of 2013's Nightmare in Silver, but even these Cybermen managed to return to dominate.

Having rebuilt itself from spare parts, a single Cyberman devastated Hedgewick's World of Wonders. Kidnapping the Eleventh Doctor's companions Angie and Artie, three million sleeping Cybermen were suddenly rewoken using their brain patterns.

Another bomb was detonated, destroying the planet and the upgraded Cybermen. As always, one tiny Cybermite managed to cling to survival, and one Cybermite is enough to rebuild.

As long as the Cybermen are on a mission to delete, upgrade and conquer, the Cyber Wars will continue.