This is one of my favourite riddles ever, and it’s a genuine brain teaser, until you fully grasp the concept. It’s a bit confusing because it revolves around truth and lies, but then again so does life! Here goes:
You approach two talking doors. One door leads to the City of Truth, while the other door leads to the City of Liars. You do not know which door is which, and they look very much the same. However, the door that leads to the City of Liars always speaks lies, while the door that leads to the City of Truth always speaks the truth. You are able to ask only one question to determine which door is which, and then you must choose. Provided you want to visit the City of Truth, what would you ask?
I won’t even bother writing down the solution to the riddle because a) you’ll probably find someone who knows the answer, or you can look up in the internet. b) It would ruin all the fun. c) you can just contact me and /or I’ll eventually post the answer here.