Democratic presidential candidate Bernie Sanders told students at the University of Chicago Monday that's it's up to them to change the world.



The U.S. senator from Vermont graduated in 1964 from the university, where he led student protests against racially segregated housing. He returned to speak to hundreds of students inside the school's Rockefeller Chapel.



Sanders told students that "change never takes place from the top down. It always takes place from the bottom on up."

"We need the idealism and the energy and the intelligence of millions of young people to join us in the fight to make America the kind of country we know it must become," Sanders said. "There is nothing that I am telling you today that is pie-in-the-sky, that is utopian. Nothing."



He also discussed the importance of one of the messages Pope Francis emphasized during his visit to America.



“Let me touch on another subject that pope Francis mentioned and has mentioned for years and mentioned when he was here in the United States,” Sander said. “That is as human beings and adults we need to understand that it is our responsibility, our moral responsibility to leave this planet in a way that is habitable and healthy for our children and our grandchildren.”



He said he learned about organized labor and democratic socialism and the fight for social justice.



Sanders has advocated for free college tuition at public universities.