1) The Mona Lisa, painted by Leonardo da Vinci, is one of the most famous and valuable artworks in the world.

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

3) The #MeToo movement, originating in 2006 and gaining widespread attention in 2017, raised awareness about sexual harassment and assault, encouraging survivors to share their experiences and promoting discussions on consent and gender equality.

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