1) The word "oxygen" contains two vowels: O and E.

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

3) The naming of cyclones varies depending on the region. For example, cyclones in the Atlantic and eastern Pacific Ocean are named using a predetermined list of names.

4) The Olympic Games, originating in ancient Greece, were revived in 1896 and are now held every four years, bringing together athletes from around the world.