1) The word "yesterday" contains three vowels: E, A, and A.

2) The ancient Egyptian civilization, with its impressive pyramids, pharaohs, and hieroglyphics, flourished along the Nile River for thousands of years.

3) The tongue of a blue whale is so big that about 50 people could stand on it.

4) George Clooney is an American actor, filmmaker, and activist. He gained fame for his role in the television series "ER" and has since starred in successful films such as the "Ocean's" trilogy, "Syriana," and "Up in the Air," winning several awards for his performances.