What is considered the hardest riddle in the world?

• In a street there are five houses, painted five different colors. In each house lives a person of different nationality. These five homeowners each drink a different kind of beverage, smoke a different brand of cigar and keep a different pet.
  
  Who owns the fish?
  
  Clues: The British man lives in a red house. The Swedish man keeps dogs as pets. The Danish man drinks tea. The Green house is next to, and on the left of, the white house. The owner of the green house drinks coffee. The person who smokes Pall Mall rears birds. The owner of the yellow house smokes Dunhill. The man living in the center house drinks milk. The Norwegian lives in the first house. The man who smokes Blends lives next to the one who keeps cats. The man who keeps horses lives next to the man who smokes Dunhill. The man who smokes Blue Master drinks beer. The German smokes Prince. The Norwegian lives next to the blue house. The Blends smoker lives next to the one who drinks water.
  
  
• I turn polar bears white and I will make you cry. I make guys have to pee and girls comb their hair. I make celebrities look stupid and normal people look like celebrities. I turn pancakes brown and make your champagne bubble. If you squeeze me, I'll pop. If you look at me, you'll pop. Can you guess the riddle?
  
  
• If a tree falls in the woods and no one is around to hear it, does it still make a sound?
  
  
• You are killed in a plane crash and find yourself in front of 2 doors: one leads to heaven and one will lead you to hell for eternity. There is an identical troll at each door. You find instructions posted on the wall behind you. You can ask only one question and you can only direct it to only one of the trolls. One troll will always lie to you -- regardless of your question -- and the other will always tell you the truth. And only the trolls themselves know which one will lie and which one will be truthful. That is all that you are told....
  
  What is the one and only question that will ensure you passage to heaven, and why?

First answer by ID1146363325. Last edit by Topdecker577. Contributor trust: 0 [recommend contributor]. Question popularity: 49 [recommend question]