20 October

20 October was a date.

In 1854 in Sevastopol, a Crimean War soldier wrote:
 * "Day and night, the pounding of the boat continues. Amid the thunder of artillery, I snatch a few moments to write to you. Here, the harbour is full of drift timber, broken into the smallest fragments, and, horrible to relate, trunks of human bodies all mutilated and torn." (AUDIO: The Angel of Scutari)

In 1901, the Lankester sank during its yearly voyage from Madagascar to New Orleans. (AUDIO: Cryptobiosis)

In 2820, the cathedrals of the Gothica colony were suddenly filled with people claiming to be from the future. They warned that in one hundred years and two days the entire colony would be overrun with Weeping Angels. Indeed, the cathedrals of the Gothica colony were overrun with Weeping Angels on 22 October 2920. (PROSE: Time Traveller's Diary)

Behind the scenes
According to an image released on the official Class Facebook page, some of the events of The Coach with the Dragon Tattoo occurred on 20 October 2016. In-universe dating, however, places this first inspection on 25 October, with the final confrontation with the Leaf Dragon taking place on the 27th.