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

2) The Federal Reserve System, often referred to as the Fed, is the central banking system of the United States.

3) The insurance industry is one of the oldest industries in the world, with roots dating back thousands of years.

4) The word "island" contains two vowels: I and A.