1) The musical "Les Misérables" is one of the longest-running shows in the West End and Broadway, with over 13,000 performances.

2) 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.

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

4) The concept of civil rights pertains to the rights and freedoms that individuals possess as members of a society, including equality before the law, freedom of expression, and protection against discrimination.