1) The political spectrum often includes the terms "left" and "right," with left-leaning ideologies generally advocating for social equality and progressive policies, while right-leaning ideologies support traditional values and limited government intervention.

2) The Mona Lisa, painted by Leonardo da Vinci, is one of the most famous and valuable artworks in the world.

3) The United Nations (UN) is an international organization founded in 1945 with the goal of promoting peace, security, and cooperation among nations through diplomatic and political means.

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