When it comes to using perfect punctuation, you'd expect the British Library to be on top of their game.
But some social media users were horrified to discover a piece of punctuation 'missing' from a sign outside of the prestigious building in London.
A photo of the sign, which is intended to advertise what's inside the library, was shared on Twitter by a user named Dr Peter Hornsby.
His post quickly went viral, garnering over 20,000 likes and more than 3,400 retweets - but can you see what people thought was wrong with the sign?
Dr Hornsby captioned his post: "Great advert from the British Library."
The sign reads: "Shops. Cafés. The whole wealth of human knowledge, endeavour and experience to date. Events. Exhibitions."
And while many might think this is perfectly fine, others were quick to argue that the British Library should have included an Oxford comma after the word endeavour.
The controversial piece of punctuation is typically used as the final comma in a list of three or more things to help prevent confusion, being placed before the words 'and' or 'or'.
People on Twitter were divided over whether or not it should have been used here.
One person replied, saying: "Love it! But where is the Oxford comma?????"
Another wrote: "The lack of the Oxford comma is killing me."
A third added: "Of all the places, I would expect the British Library to employ an Oxford comma."
However others didn't think the piece of punctuation needed to be used in this instance.
Someone else said: "I don’t think an Oxford comma is necessary in this particular sentence; it isn’t ambiguous. Besides, isn’t it an americanism?"
A second thought the Oxford comma was "optional" here.
Whatever your stance on it, the British Library didn't seem to bothered about not having used the Oxford comma.
A spokesperson told MailOnline they had received a "very positive response" after the sign went up earlier this month.
