This quiz about London Underground stations described with emojis is going viral.
Some of them, like 5 and 13, are pretty tricky, but everyone is going mad over number 12.
No one can work it out, not even TfL staff.
There are a lot of (not particularly convincing) theories going round as to what the correct answer could be.
Some people think the answer could be Mornington Crescent, as a reference to a game played on satirical BBC Radio 4 panel show I'm Sorry I Haven't a Clue.
But the most likely answer seems to be that number 12 is purely a troll, designed to get people to share the quiz, in which case it has worked perfectly.
It's a troll – a very clever troll.I buy the Mornington Crescent theoryI KNOW THE ANSWER, I AM A GENIUS
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So what do you think, is number 12 a troll or is there an answer?
vote votesIt's a troll – a very clever troll.
vote votesI buy the Mornington Crescent theory
vote votesI KNOW THE ANSWER, I AM A GENIUS