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

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

3) The Earth's core is primarily composed of iron and nickel and is as hot as the surface of the sun.

4) Brad Pitt is an American actor and film producer. He has starred in a wide range of films, including "Fight Club," "Inglourious Basterds," and "Once Upon a Time in Hollywood," and has received critical acclaim and numerous awards for his performances.