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 global response to climate change includes the Paris Agreement, an international treaty aiming to limit global warming and strengthen countries' efforts to address climate change through mitigation and adaptation strategies.

3) The coldest known temperature in the universe was achieved in a laboratory in 2019, reaching a fraction of a degree above absolute zero (-273.15 degrees Celsius).

4) 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.