War zone (The Pilot)

As a part of his plan to defeat the sentient oil, the Twelfth Doctor went to a war zone in the Dalek-Movellan War.

He took the TARDIS there with the intention of finding "the deadliest fire in the universe", an energy blast from a Dalek. In order to find it, the Doctor landed in the middle of the Dalek-Movellan War. (TV: The Pilot)

Behind the scenes
During the scene in which the TARDIS travels there, a short scene from The Doctor's Wife is re-used in which the TARDIS leaves the through the bubble universe rift for the House planetoid.