1986 Cyberman invasion of Earth as there is no need for a conjectural name.
Talk about it here.
The invasion Edit
to be added
Professor Allison Williams led the scientific team which investigated the Cyberman ship in Antarctica. (PROSE: The Power of the Daleks) The Cyberships leftover from the invasion were examined and exploited by humans, allowing them to make advances in space travel, leading Sarah Jane Smith to describe the return of Mondas as "both the greatest disaster and most astonishing blessing ever to have happened to the human race." (PROSE: The Power of the Daleks)