Brain teaser for all?

You are in a room with two identical doors. ( no other means of entering or leaving the room). One door leads to a good life, the other to hell. Both doors are guarded by identical guards. The only difference between them is that one can only tell the truth and the other can only tell lies. You have one qestion to ask either of the guards....remembering you dont know which one is which. What do you ask in order to find out which door is which????