1) The Mongol Empire, under the leadership of Genghis Khan, became the largest contiguous empire in history, spanning from Asia to Europe.

2) 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.

3) Orchids are one of the largest families of flowering plants, with over 25,000 species.

4) The deepest part of the ocean is the Mariana Trench, reaching a depth of about 36,070 feet (10,994 meters).