"Rassilon's Lament"
From Tardis Wiki, the free Doctor Who reference
"Rassilon's Lament" was a Gallifreyan musical piece. The notes were present on a painting hung in the Capitol. If the piece was played upon the Harp of Rassilon, a secret chamber would open. Borusa, the Fifth Doctor and Romana II all made use of this. (PROSE: Blood Harvest, TV: The Five Doctors)
