1) The Great Barrier Reef in Australia is the largest living structure on Earth and can be seen from space.

2) The first bank in the world, Banca Monte dei Paschi di Siena, was established in Italy in 1472 and is still in operation today.

3) Celtic mythology encompasses the folklore and legends of the Celtic peoples across Europe, particularly in regions like Ireland, Scotland, and Wales. It features deities like Morrigan, Cernunnos, and Brigid, and delves into themes of nature, magic, and the heroic exploits of legendary figures like Cu Chulainn.

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