1) The word "piano" contains three vowels: I, A, and O.

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 Epic of Gilgamesh, originating from ancient Mesopotamia, is one of the oldest surviving works of literature and tells the story of the heroic king Gilgamesh and his quest for immortality. It explores themes of friendship, mortality, and the relationship between humans and the divine.

4) The musical "Les Misérables" is one of the longest-running shows in the West End and Broadway, with over 13,000 performances.