1) A single bolt of lightning can heat the surrounding air to temperatures five times hotter than the surface of the sun.

2) Cows have best friends and can become stressed if they are separated.

3) The world's most expensive car is the Bugatti La Voiture Noire, which sold for over $18 million.

4) The Dow Jones Industrial Average (DJIA) is a stock market index that tracks the performance of 30 large, publicly owned companies in the United States.