Today I learned about an Internet phenomenon in Germany, where people deny the existence of the city of Bielefeld, a city of 330,000 inhabitants, and claim that the existence of the city is a conspiracy.
This is a humorous conspiracy theory first published on an Internet forum in 1993 and is now one of the most popular jokes in Germany. Even the German chancellor questioned the existence of the city after she visited it.
Source: https://en.wikipedia.org/wiki/Bielefeld_Conspiracy