KENT, Ohio (AP) — Dean Kahler flung himself to the ground and covered his head when the bullets started flying. The Ohio National Guard had opened fire on unarmed war protesters at Kent State University, and Kahler, a freshman, was among them.

M1 rifle rounds hit the ground all around him. “And then I got hit,” Kahler recalled, more than 50 years later. “It felt like a bee sting.” But it was far worse than that — a bullet had gone through his lung, shattered three vertebrae and damaged his spinal cord. He was paralyzed.

Four Kent State students were killed and Kahler and eight others were injured when National Guard members fired into a crowd on May 4, 1970, following a tense exchange in which troops used tear gas to break up an anti-war demonstration and protesters hurled rocks at the guardsmen. It was a watershed moment in U.S. history — a violent bookend to the turbulent 1960s — that galvanized campus protests nationwide and forced the temporary shutdown of hundreds of colleges and universities.