2 guards riddlehttps mail.yahoo.com d folders 1

A classic riddle!

Here's the solution:

Two guards are standing at the entrance of a castle. One of them always tells the truth, and the other always lies. You don't know which one is which. You can ask one of them only one question to figure out which one is the truth-teller.

What question should you ask?

Think you know the answer?