Tin soldiers and Nixon coming / We’re finally on our own / This summer I hear the drumming / Four dead in Ohio.

On this day in 1970, as anti-government tensions flared on college campuses across America following President Richard Nixon‘s expansion of the Vietnam War into Cambodia, a group of activists gathered on the campus of Kent State University in Ohio for a peaceful protest of the invasion of Cambodia and the newfound National Guard presence on campus following the burning of an ROTC building a few days prior. While the National Guard officially disallowed the protest, thousands of students showed up anyway. Just after noon, as animosity between the gathered protestors and the National Guard began to boil over, a group of guardsmen opened fire on the students for 13 seconds. Four students were killed in the shooting. Nine more were injured. The Kent State massacre remains one of the most notable incidents of violence on U.S. soil during a time of widespread political and societal unrest.

A few weeks later, LIFE magazine ran a cover story on the atrocities that took place on that sunny day in Kent featuring shocking photographs and descriptions of the incident. So the story goes, David Crosby showed Neil Young the magazine at the house of Crosby, Stills, Nash & Young tour manager Leo Makota. In a visceral reaction to the story, Young quickly grabbed a guitar and wrote a song about the massacre: “Ohio”.

“I remember getting nuts at the end of the song, I was so moved,” Crosby told Young’s biographer Jimmy McDonough. “I was freaked out because I felt it so strongly, screaming, ‘Why? Why?'”

Crosby and Young quickly flew to Los Angeles where they linked up with Graham Nash and Stephen Stills to record the track in just a few quick takes. The single (opposite Crosby’s “Find The Cost Of Freedom”) was rushed into production and within a matter of weeks, it had hit record store shelves—with a sleeve depicting the portion of the Bill of Rights that guarantees the right to peaceful assembly. In addition to the inherent power of the song, the speed with which the track was turned around made its social impact that much stronger.

Hear Graham Nash explain the writing/recording process and perform the song below:

Graham Nash Talks “Ohio” Backstory on Howard Stern Show

[Video: The Howard Stern Show]

While the single quickly came out after being recorded in 1970, the studio recording of “Ohio” was not featured on an album until 1974’s So Far. Listen to the album version of “Ohio” below:

Crosby, Stills, Nash & Young – “Ohio”

[Video: Crosby, Stills, Nash & Young – Topic]

The Neil Young-penned song about the violent incident in Ohio quickly became—and has long remained—one of the most influential protest songs in the American music canon. In the liner notes of his Decade (1977) compilation album, Young referred to Kent State as “probably the biggest lesson ever learned at an American place of learning.”

As we observe the 50th anniversary of the Kent State massacre today, take a listen to some powerful renditions of “Ohio” from through the years:

Neil Young – “Ohio” – Live At Massey Hall 1971

[Video: neilyoungchannel]

Crosby, Stills, Nash & Young – “Ohio” [Pro-Shot] – Golden Gate Park – San Francisco, CA – 11/3/91

[Video: neilyoungchannel]

Crosby, Stills, Nash & Young – “Ohio” – Air Canada Centre – Toronto, ON – 3/30/2000

[Video: addresses]

David Crosby & Jason Isbell – “Ohio” – Newport Folk Festival 2018

[Video: Bob McGrath]

The Isley Brothers – “Ohio/Machine Gun” [Neil Young/Jimi Hendrix covers] – Live at The Bitter End 1972 – New York, NY

[Video: The Isley Brothers]

Phil Lesh & The Terrapin Family Band – “Ohio” – Apollo Theater – New York, NY – 9/7/18

[Video: InnovAsianTravel]

Ben Harper – “Ohio” – Arena Civica – Milan, Italy – 7/20/11

[Video: gastainer]

Jon Batiste, Leon Bridges, Gary Clark Jr. – “Ohio”