1) The most-watched TV series finale in the United States was "MAS*H," with an estimated 105 million viewers.

2) The first photograph of a black hole was captured in 2019 using a network of telescopes around the world.

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