1) The fall of the Berlin Wall in 1989 symbolized the end of the Cold War and the reunification of East and West Germany.

2) A single bolt of lightning can heat the surrounding air to temperatures five times hotter than the surface of the sun.

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

4) Cyclones are fueled by warm ocean waters and atmospheric conditions that allow the formation of thunderstorms.