1) The world's first credit card was introduced in 1950 by Diners Club.

2) Oprah Winfrey is an American media mogul, television host, actress, and philanthropist. She is best known for hosting "The Oprah Winfrey Show," which became the highest-rated talk show in TV history, and for her influential role in the entertainment industry.

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

4) The word "country" contains three vowels: O, U, and Y.