1) The national animal of Australia is the kangaroo.

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

3) The Danube River, flowing through ten countries in Central and Eastern Europe, is the second-longest river in Europe. It has played a significant role in the cultural and economic development of the regions it traverses and is a popular waterway for river cruises.

4) The New England Patriots and the Pittsburgh Steelers hold the record for the most Super Bowl wins, with six championships each.