1) Michael Phelps, an American swimmer, has won a total of 28 Olympic medals, including 23 gold medals, making him the most decorated Olympian of all time.

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

3) The word "orange" contains three vowels: O, A, and E.

4) The first successful human heart transplant was performed by Dr. Christiaan Barnard in 1967.