An Australian physicist recently discovered a 99-year-old typo. In a dictionary. That has been used as a reference for other dictionaries.
Dr. Stephen Hughes, from the University of Technology in Brisbane, discovered the mistake while researching an article for science teachers. He brought to the attention of Oxford University Press that the definition for the word “siphon” was incorrect. Oxford's definition states siphons function due to atmospheric pressure, but Hughes says in actuality, they function due to gravity. The definition had been incorrectly repeated since it was first published in 1911.
OED will make the change in the next edition, but it is unknown how many other sources used Oxford's definition as a resource.
I'm a nerd. I would have loved to have been the person to find this typo. But even if I had read it, I'm not a scientist so I probably wouldn't have even known it was incorrect.