1) The book series "The Chronicles of Narnia" by C.S. Lewis has sold over 100 million copies worldwide.

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

3) The concept of reinsurance, which is insurance for insurance companies, originated in the 17th century.

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