1) The process of nuclear fusion powers the sun and other stars, fusing hydrogen atoms together to form helium and releasing vast amounts of energy in the process.

2) The Pacific Ocean is the largest ocean on Earth, covering more than 30% of the planet's surface.

3) The Age of Exploration, during the 15th and 16th centuries, saw European explorers such as Christopher Columbus and Vasco da Gama reach new lands and establish trade routes.

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