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

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

3) The name "Bluetooth" comes from the 10th-century Danish king, Harald Bluetooth, who united Denmark and Norway.

4) The United Nations Security Council is responsible for maintaining international peace and security, with five permanent members (China, France, Russia, the United Kingdom, and the United States) holding veto power over resolutions.