The Bielefeld Conspiracy is a satire of conspiracy theories that originated in 1994 in the German Usenet, which claims that the city of Bielefeld does not actually exist, but is an illusion propagated by various forces. Originally an internet phenomenon, the conspiracy has since been represented in the city’s marketing, and referred to by Chancellor Angela Merkel.
In 1999, five years after the myth started to spread, the city council released a press statement titled Bielefeld gibt es doch! (Bielefeld does exist!). However, the statement’s publication date – April 1, 1999 (April Fools’ Day) – was ill-chosen as it unwittingly played right into the humorous conspiracy. [x]
Source: Ultra Facts