1) The deepest part of the ocean is the Mariana Trench, reaching a depth of about 36,070 feet (10,994 meters).

2) The unicorn is the national animal of Scotland.

3) The ancient city of Athens, Greece, is often considered the birthplace of democracy, where citizens had a say in the decision-making process.

4) The longest-running TV show in history is "The Simpsons," which has been on the air since 1989 and has over 700 episodes.