Fifty years ago today, on April 23, 1968, hundreds of students at Columbia University in New York started a revolt on campus. They occupied five buildings, including the president’s office in Low Library, then students barricaded themselves inside the buildings for days. They were protesting Columbia’s ties to military research and plans to build a university gymnasium in a public park in Harlem. The protests began less than three weeks after the assassination of Dr. Martin Luther King Jr. The 1968 Columbia uprising led to one of the largest mass arrests in New York City history—more than 700 people arrested on April 30. It also inspired student protests across the country. Today, we spend the hour looking back at this pivotal moment. We are joined by Raymond Brown, former leader of the Student Afro-American Society; Nancy Biberman, a Barnard College student who joined the protests as a member of Students for Democratic Society; Mark Rudd, chair of the Columbia University chapter of SDS during the student strike; Juan González, Democracy Now! co-host who was a Columbia student and strike organizer; and Paul Cronin, editor of the new book “A Time to Stir: Columbia ’68.” We also feature excerpts from the 1968 documentary “Columbia Revolt” by Third World Newsreel.