1906 San Francisco earthquake
From Tardis Wiki, the free Doctor Who reference
The 1906 San Francisco earthquake struck the city on 18 April, 1906. Caleera hoped to exacerbate it with her gift to destroy Earth, but the Eighth Doctor stopped her by transferring it into his TARDIS. The earthquake caused massive destruction and a fire on Telegraph Hill.
Helen Sinclair once watched a film about the earthquake starring Clark Gable. (AUDIO: The Gift)