Fall of Gallifrey
From Tardis Wiki, the free Doctor Who reference
The Fall of Gallifrey occurred when the Eye of Time, possessed by the Time Lords, was lost. The Eye fell into the hands of the New Dalek Paradigm after the Last Great Time War. (GAME: City of the Daleks)
The "Fall of Gallifrey" presumably referred to the Time War, in which Gallifrey, along with the Time Lords and the Daleks, was destroyed by the Doctor using the Moment.