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 first consumer digital video recorder (DVR), the TiVo, was introduced in 1999 and allowed users to record and store television programs for later viewing.

3) The Grand Canyon, located in Arizona, United States, is a massive and awe-inspiring natural formation carved by the Colorado River. It is approximately 446 kilometers (277 miles) long, up to 29 kilometers (18 miles) wide, and reaches a depth of over 1.8 kilometers (1.1 miles).

4) The phenomenon known as "black holes" occurs when matter is crushed into an infinitely small space, creating a gravitational pull so strong that nothing can escape.