You are walking down a cave when you come to two doors guarded by two guards. One door leads to paradise, and the other instant death. One of the guards always lies, and the other always tells the truth. The guards are identical, and you cannot tell which guard is which. At your disposal is the ability to ask one guard one question. No more, no less. What is the one question you may ask either guard, and figure out which door is which?
NOTE - Anyone who has seen the movie Labirynth, please do not answer