One leading to hell, one leading to heaven, they are both identical. The doors of both are guarded by Angels, one tells lies and one tells the truth. The one that tells lies covers the door to hell and the one that tells the truth to heaven.
What question do you ask to find out which is the correct door to use, you can only ask one question and the same question to both.
(Assuming you want to go pick the correct choice.)
Ricky Gervais show.