The San Francisco Armory meme, often referred to as 'Kink Castle,' centers around the massive, fortress-like brick building in the Mission District of San Francisco. While originally built as an arsenal for the US National Guard, it gained internet notoriety after being purchased by the adult film company Kink.com in 2006. Memes featuring the building usually rely on the 'those who know vs. those who don't know' trope, where the imposing architecture suggests a serious government facility to the uninitiated, while those familiar with internet culture recognize it as a former hub for adult content production. It serves as a visual shorthand for hidden knowledge, niche internet subcultures, and the surprising history of urban landmarks.