Australia doesn’t exist. The signs were there the whole time: in what country is the only thing more poisonous than the snakes the spiders? How did we ever believe that kangaroos were a thing?

This discovery, believed by some to be a joke or a conspiracy theory, has been circulating on social media in recent weeks after being formulated on Reddit in early 2017. Except it turns out not to be the only theory of its kind: through the years, online sleuths have found that all sorts of places don’t exist.

High on the list is Finland, the country some believe lies between Russia and Sweden, and that allegedly fought a valiant rearguard action against Soviet invasion in the runup to the second world war. This theory was also born on Reddit, in 2015. Finland, the user Raregan explained, was merely a fictional creation designed to create fishing quotas to aid the export of sushi to Japan from Russia.

Last summer, another Reddit user suggested the Italian region of Molise – population 300,000 – doesn’t exist, apparently as the result of an Italian in-joke, while Brazilians have had for at least five years an online theory that the north-western state of Acre doesn’t exist or else is a land that time forgot, still populated by dinosaurs.

The joke – or painstakingly well-evidenced and argued theory – that a country or region doesn’t exist turns out to be one of the oldest memes on the internet. As early as 1993, German users of Usenet – a network of online discussion forms (or bulletin boards), which predates the web – had a running joke that the Westfalian town of Bielefeld (population 300,000, funnily enough) was a fiction maintained by the CIA, Mossad, aliens or some combination of the three.

The joke has crossed decades, online platforms, language barriers and international cultures, and keeps coming back.“The beauty of memes is that they are malleable and everyone can have their own spin on things and get involved in the joke,” says writer Mollie Goodfellow. “I think it says that we all like to be in on the joke, especially online, where often different cliques and subgroups can form.”

In these days of fake news and mainstream-media conspiracies, though, it doesn’t do to take anything for granted – so G2 contacted a diplomatic source, who agreed to speak off the record and confirm what they could about the existence (or otherwise) of Finland and Australia.

“Hang on, let me look out the window,” the source replied, before confirming Finland existed.

The source was unable to provide similar confirmation for Australia.