Democratic presidential candidate Bernie Sanders is recalling his start in the civil rights movement at the University of Chicago in the early 1960s, but says there’s still more work to do.

The U.S. senator from Vermont and democratic socialist spoke Sunday night at Chicago’s Navy Pier. Earlier Sunday he joined other 2020 hopefuls and civil rights leaders in Selma, Alabama, to commemorate the 1965 march for voting rights that came to be known as “Bloody Sunday.”

Sanders was active in the campus chapter of the Congress of Racial Equality at the University of Chicago, protesting discrimination and housing segregation.

Sanders says that while the Chicago activism was significant it didn’t compare to what was happening in the South. He says it’s “incomprehensible” that people of color and poor people still fight for voting rights.