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

2) Bats are the only mammals capable of sustained flight.

3) The Great Wall of China is a UNESCO World Heritage site and one of the most iconic man-made structures in the world. It stretches over 21,196 kilometers (13,171 miles) and was constructed to protect the Chinese empire from invasions during ancient times.

4) The human body contains enough carbon to make over 9,000 pencils.