1) The concept of compound interest can be attributed to the ancient Babylonians, who used it in their banking practices.

2) Serena Williams, an American tennis player, has won a total of 23 Grand Slam singles titles, making her one of the most successful players in the history of the sport.

3) The word "pencil" contains two vowels: E and I.

4) The musical "The Phantom of the Opera" has been running in London's West End since 1986, making it the longest-running musical in history.