21 February

21 February was the date of the annual Zygon Celebrity-Lookalike Competition. (PROSE: Time Traveller's Diary)

In 1863, the Fifth Doctor and Nyssa's investigation into a connection between the spirits of Adric, Tremas and Prince Albert came to an end on the banks of the River Clyde. The duo left Scotland, secure in the knowledge that they'd put their metaphysical adventure behind them — but also cognisant of the fact that they'd only kept Queen Victoria safe; she would still mourn for her beloved Albert for many years to come. (PROSE: Empire of Death)

On the same day in 1865, while on duty in Gable, West Virginia, Captain Will Johnson wrote a letter to his lover, Claire Bartlett. (PROSE: Blood and Hope)

In 1968, the Sixth Doctor left Henry Gordon Jago and Professor George Litefoot in the Red Tavern in London, mistakenly believing that it was the 1890s. (AUDIO: Voyage to the New World)

Exactly ten years later, workers in Mexico City uncovered the sacrificial stone at the base of the Great Temple of the Aztecs. (PROSE: The Left-Handed Hummingbird)