1) The tongue of a blue whale is so big that about 50 people could stand on it.

2) The concept of insurance dates back to ancient times when merchants would distribute their goods across different ships to reduce the risk of losing everything in a single event.

3) The word "book" contains two vowels: O and O.

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