The Kent States you don’t know about

( CNN) On May 4, 1970, 13 seconds of gunfire seemed to draw America to a stall.

On the Midwestern campus of Kent State University, four students had been killed and nine others were injured when Ohio National Guard representatives opened fire on demonstrators protesting the Guard’s presence and the expansion of the Vietnam War.

The event so sickened the nation that more than 500 colleges were shut down as students responded to the killings with outraged protest. Life store and Newsweek dedicated treat storeys to the incident, with Newsweek and The New York Times famously showcasing the now-iconic photograph of a young lady screaming as she knelt over the body of a Kent State student.