Because for some reason I didn't see any reference to it today : May 4, 1970
From Wikipedia, Kent State Shootings
The Kent State shootings (also known as the May 4 massacre or the Kent State massacre) were the shootings of unarmed college students protesting the Vietnam War at Kent State University in Kent, Ohio, by burning the campus ROTC building and throwing rocks at the Guardsmen. The shootings were perpetrated by members of the Ohio National Guard on May 4, 1970. Twenty-nine guardsmen fired approximately 67 rounds over a period of 13 seconds, killing four students and wounding nine others, one of whom suffered permanent paralysis.Some of the students who were shot had been protesting the Cambodian Campaign, which President Richard Nixon announced during a television address on April 30. Other students who were shot had been walking nearby or observing the protest from a distance.There was a significant national response to the shootings: hundreds of universities, colleges, and high schools closed throughout the United States due to a student strike of 4 million students, and the event further affected public opinion, at an already socially contentious time, over the role of the United States in the Vietnam War.
Because I was feeling a lot of rage today I thought I would leave you with the lyrics to the song that Crosby Stills and Nash wrote.