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

2) 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.

3) The average person spends around six months of their lifetime waiting for red lights to turn green.

4) 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).