What question do you ask to the pilgrim?

Surely you've heard of the Pilgrim's Riddle. There's a pilgrim standing at a fork in the road. You know that one side of the fork leads to Heaven and the other leads to Hell, but you don't know which one. The pilgrim came from one or the other, but you don't know whether he's an angel, who'll tell you the honest truth, or a devil, who'll lie to you as soon as look at you. You're in a hurry and only have time to ask one question. What do you ask?