1) The highest-grossing concert tour of all time is U2's "360° Tour," which earned over $735 million in ticket sales.

2) In Greek mythology, Pandora is the first human woman created by the gods. She is known for opening a forbidden box (commonly mistranslated as a "Pandora's box") and releasing various evils into the world. However, hope remains trapped inside the box, offering a glimmer of light amidst the darkness.

3) Aztec mythology, originating from ancient Mesoamerica, includes deities like Quetzalcoatl, Huitzilopochtli, and Tlaloc. It explores concepts of creation, sacrifice, and the cyclical nature of time, with intricate cosmology and rituals forming a significant part of Aztec religious beliefs and practices.

4) 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.