1) The blue whale is the largest animal to have ever existed, with an average length of about 82 feet (25 meters).

2) The concept of civil rights pertains to the rights and freedoms that individuals possess as members of a society, including equality before the law, freedom of expression, and protection against discrimination.

3) The game of baseball, often referred to as "America's pastime," is played between two teams of nine players and has a rich history dating back to the 18th century.

4) The Hubble Space Telescope, launched in 1990, has provided breathtaking images of distant galaxies and deep space.