1) The world's first car radio was invented in 1929.

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

3) The world's largest desert is the Sahara Desert in Africa, covering an area of about 3.6 million square miles (9.4 million square kilometers).

4) Banks play a vital role in the economy by facilitating the flow of funds between savers and borrowers, providing loans, and offering various financial services.