Four students were killed and nine others wounded by National Guardsmen at which Ohio university on May 4, 1970?

Four glass pyramids were built from 1984 to 1989 between the Denon and Richelieu wings of which museum? What is fourscore and seven, minus the number of syllables in a haiku? The opera based on which 1868 novel begins with four sisters in their family attic? Which four-star general became the first Black chairman of the Joint Chiefs of Staff in 1989? Four teammates, a house, a hog line and a tee line are all part of which sport? Which four-time New York governor used "The Sidewalks of New York" as his 1928 presidential campaign song? Four treaties to lessen the horrors of war were signed in which Swiss city in August 1949? Which four-winged predatory insect belongs to the order Odonata?