City of Lies or Truth Puzzle
You are at an unmarked intersection ... one way is the City
of Lies and another way is the City of Truth.
Citizens of the City of Lies always lie.
Citizens of the City of Truth always tell the truth.
A citizen of one of those cities (you don't know which) is
at the intersection. What question could you ask to them to find the way to the
City of Truth?
Source : https://www.mathsisfun.com/puzzles/city-of-lies-or-truth.html