1) The concept of proportional representation, used in some electoral systems, aims to ensure that political parties' representation in government aligns more closely with the proportion of votes they receive from the electorate.

2) The world's most expensive car is the Bugatti La Voiture Noire, which sold for over $18 million.

3) 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.

4) The construction of the Great Wall of China began in the 7th century BC and was completed over several centuries, spanning thousands of miles.