The Glorious Twenty-Fifth of May, also known as Wear the Lilac Day, is observed worldwide every May 25 by fans of Terry Pratchett’s Discworld series. This celebration commemorates the People’s Revolution of the Glorious Twenty-Fifth of May, as depicted in the novel Night Watch, which marked a significant turning point in the history of the fictional city Ankh-Morpork. Participants honor the fallen revolutionaries by gathering at the Little Gods’ Cemetery to lay lilacs and hard-boiled eggs, a token from Madame Roberta Meserole. Additionally, many wear lilac to remember the characters involved in the uprising, including Sam Vimes and Fred Colon. The day also serves as an impromptu Alzheimer’s awareness day, following Terry Pratchett's announcement of his own diagnosis in 2007, prompting fans to support Alzheimer’s research through the Match It For Pratchett campaign. The choice of May 25 was made to minimize offense, as revealed by Pratchett's business manager, and it coincides with Geek Pride Day and Towel Day, allowing for joint celebrations among fans of both Pratchett and Douglas Adams.