1) The blue whale is the largest animal to have ever existed, with an average length of about 82 feet (25 meters).

2) The concept of compound interest can be attributed to the ancient Babylonians, who used it in their banking practices.

3) The Great Barrier Reef in Australia is the largest living structure on Earth and can be seen from space.

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).