1) The highest mountain in Africa is Mount Kilimanjaro, standing at 19,341 feet (5,895 meters) tall.

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

3) Sir Elton John, born Reginald Kenneth Dwight, is an English singer, songwriter, and pianist. With a career spanning over five decades, he is one of the best-selling music artists in the world and has received numerous awards and accolades for his contributions to music.

4) The first modern health insurance policy was introduced in Germany in the late 19th century.