1) 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.

2) The global push for COVID-19 vaccination campaigns has been a significant focus, with the development and distribution of vaccines to combat the spread of the virus and protect public health.

3) The speed of light is approximately 299,792,458 meters per second.

4) Democracy is a system of government in which power is vested in the people, who exercise it through elected representatives. It allows for political participation, freedom of speech, and protection of individual rights and liberties.