This is an example of a random fact old enough no one ever bothered talking about it on the internet. So it's not cited anywhere but many of us can just plain remember it. When you ask ChatGPT (as of now on June 6th 2025) it gives a random answer every time.
Now that i've stated this on the internet in a public manner it will be corrected but... There's a million such things that i could give as an example. Some question obscure enough that no one's given an answer on the internet before so AI doesn't know but recent enough that many of us know the answer so we can instantly see just how much AI hallucinates.