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

2) The Renaissance period, which began in Italy in the 14th century, marked a renewed interest in art, literature, science, and philosophy.

3) Rihanna, born Robyn Rihanna Fenty, is a Barbadian singer, actress, and businesswoman. She has achieved great success in the music industry with hits like "Umbrella," "Diamonds," and "Work," and has also ventured into the worlds of fashion and cosmetics with her brands.

4) The world's largest desert is the Antarctic Desert, covering around 5.5 million square miles.