1) The Nile River, spanning approximately 6,650 kilometers (4,130 miles), is the longest river in the world. It flows through eleven countries in northeastern Africa, supporting various civilizations throughout history and serving as a vital source of water and transportation.

2) The world's first stock exchange was established in Amsterdam in 1602.

3) J.K. Rowling's "Harry Potter" series of books has sold over 500 million copies worldwide and has been translated into 80 languages.

4) The Great Wall of China is not visible from space without aid, contrary to popular belief.