1) Emma Watson is a British actress and activist known for her role as Hermione Granger in the "Harry Potter" film series. She has since starred in films such as "The Perks of Being a Wallflower" and has been actively involved in promoting gender equality and women's rights.

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

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

4) Sir Elton John, born Reginald Kenneth Dwight, is an English singer, songwriter, and pianist. With a career spanning over five decades, he is one of the best-selling music artists in the world and has received numerous awards and accolades for his contributions to music.