1) The abolition of slavery in the United States was officially proclaimed with the ratification of the 13th Amendment to the Constitution in 1865.

2) The first successful mass-produced personal computer, the IBM PC, was introduced in 1981 and played a significant role in popularizing the use of computers in homes and offices.

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

4) The film "Gone with the Wind" won eight Academy Awards, including Best Picture, and remains one of the highest-grossing films of all time when adjusted for inflation.