1) The Sahara Desert, located in North Africa, is the largest hot desert in the world, covering an area of about 9.2 million square kilometers (3.6 million square miles). It is characterized by vast stretches of sand dunes, rocky plateaus, and extreme temperatures.

2) Cyclones, also known as hurricanes or typhoons, are powerful tropical storms characterized by low-pressure centers and strong winds.

3) The discovery of the Americas by Christopher Columbus in 1492 opened up new trade routes and had a profound impact on world history.

4) The tongue of a blue whale is so big that about 50 people could stand on it.