A 25th anniversary, such as Queen Elizabeth II's in 1977, is called a silver what?

A 21-hour production of which Goethe work was a highlight of Expo 2000 in Hanover, Germany? A 22-year-old Belgian soldier was the model for which French sculptor's 1877 work "The Age of Bronze"? A 24-carat gemstone weighs 4.8 of which metric units? A 25-year search with telescopes ended with the discovery of which object in 1930? A 1956 three-cent stamp honored the 50th anniversary of which Wyoming national monument? Which three-term U.S. congresswoman made a failed run for national office in 1984? A 32-room, 14-bathroom mansion at 518 Crestview Drive in Beverly Hills was home to the family on which sitcom? A 35-foot-long muslin stocking was used to create the cyclone in which 1939 film?