1) The eye of a cyclone is a region of calm, relatively clear skies and light winds at the center of the storm.

2) The Eiffel Tower can be 15 cm taller during the summer due to thermal expansion.

3) 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).

4) The Hubble Space Telescope, launched in 1990, has provided breathtaking images of distant galaxies and deep space.