They would have been heroes: On this day 43 years ago, the National Guard shot dead Jeffrey Miller, Alison Krause, William Schroder, and Sandra Scheuer, all students at Kent State University in Ohio who were protesting the Vietnam War.

The Kent State shootings—also known as the May 4 massacre or the Kent State massacre—occurred at Kent State University in the U.S. city of Kent, Ohio, and involved the shooting of unarmed college students by the Ohio National Guard on Monday, May 4, 1970. The guardsmen fired 67 rounds over a period of 13 seconds, killing four students and wounding nine others, one of whom suffered permanent paralysis.