What has four syllables, four Rs, and is essentially unpronouncable for anyone who's not a French native?
As far as we're concerned - the answer is serrurerie, which means locksmith.
And our readers agree. In fact, serrurerie was the most common answer when we put the call out recently (click here for the full top ten).
But just how hard is it to say?
Our reporter Oliver Gee scoured the streets of Paris to ask tourists to try and pronounce it - and got very mixed responses. Check out the video below.