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

2) The Great Barrier Reef in Australia is the largest coral reef system in the world and is visible from space.

3) The total length of your blood vessels can circle the Earth more than twice.

4) The construction of the Great Wall of China began in the 7th century BC and was completed over several centuries, spanning thousands of miles.