Wednesday marks 46 years since four students were shot and killed at Kent State University.

On May 4, 1970, members of the National Guard fired into the crowd. Four students were killed and nine were injured.

The National Guard was called to the campus to oversee student protests regarding the Vietnam War. When President Nixon declared the United States' intention to attack Viet Cong, protests followed.

According to the university, the protests started peacefully, but became confrontational as protestors clashed with police and violence ensued. The National Guard was called in on May 2.

As more than 1,000 protestors and demonstrators occupied the campus, almost 1,000 members of the National Guard arrived.

On May 4, a rally was held at noon, despite the university attempting to ban it.

Approximately 3,000 people filled the Kent State commons area and the National Guard dispatched about 100 guardsmen with military rifles to the area.

Demonstrators were ordered to disperse, which resulted in rocks being thrown at the guardsmen. The pack of protestors moved toward Blanket Hill. Twenty-eight guardsmen fired into the crowd. Between 61 and 67 shots were fired within a 13-second span.

The four students shot and killed were Jeffrey Miller, Allison Krause, William Schroeder and Sandra Scheur.

The university closed for six weeks following the shootings.

Several questions and much debate still surrounds the shootings, including whether the National Guard should have been called to the campus, and why the guardsmen shot into the crowd.

For more information on the May 4, 1970 shootings, click here.