10. Many traffic lights and lift buttons are actually placebo buttons – in other words, they do nothing at all when pressed. They exist to give the presser the feeling of control. [Source]

11. When tickled, rats laugh. Here is an excellent video clip demonstrating this fact.

12. At certain points on Mercury’s surface, an observer would be able to see the Sun rise about halfway, then reverse and set before rising again, all within the same Mercurian day. Having said that, one day on Mercury is 176 earth days. [Source]

13. In his lifetime, Adolf Hitler had four relationships (three confirmed and one suspected). Of those relationships, all four women attempted suicide at least once, and two succeeded.

14. Sand sharks have a very unique gestation. A mother shark develops two embryos when impregnated. The stronger of the two embryos eats the other before it is born. This is called “intrauterine cannibalism”. It will also eat any other eggs that exist in the mother at the time.

15. The center of a rainbow is the shadow from your head. A primary rainbow is always somewhere on an arc 42 degrees around the shadow of your head (called the anti solar point). So brightly illuminated rain must be in this direction away from you to see a rainbow. [Source]