2000 Dalek invasion

Forced by Davros to reveal to him the Daleks' future defeats during the Genesis Incident, the Fourth Doctor recounted a Dalek invasion of Earth in the year 2000. He stated that the magnetic properties of the Earth's core itself helped to defeat the Daleks, as well as the determination of human resistance fighters. (TV: Genesis of the Daleks) By one account, this was evidence of a crucial divergence in history which allowed Daleks to come to power earlier, allowing them to one day destroy all life. (PROSE: A History of the Universe)

The Fourth Doctor's recollection of events bore similarities to the 22nd century Dalek invasion of Earth and the failure of Project Degravitate, which the First Doctor was witness to. (TV: The Dalek Invasion of Earth)