Does the human body contain gold? Can eating spinach really make you stronger? Quench your curiosity with the fascinating facts behind every-day mysteries. Why Do Camels Have Humps? Why are Stop Signs Octagonal? Why are Traffic Lights Red, Yellow, and Green? Why Do We Cry When We Chop Onions? Why Does Our Hair Turn Grey? Why Do Our Muscles Sometimes Ache After Excercise? Why Do We Cry When We're Sad or Hurt? What are Cavities? That's Crazy! Smartphones are Covered in More Germs than a Toilet Seat! Why Do Skunks Smell so Bad? Why does the tower of Pisa lean? Why do some animals have tails?