Bernie Sanders speaks at the University of Chicago

CHICAGO (WLS) -- Democratic presidential candidate Bernie Sanders was in Chicago Monday as new polls show him gaining momentum against Hillary Clinton.

A poll in New Hampshire gives sanders a 16 point lead over Clinton.

He drew a big crowd at an event held by the University of Chicago's Institute of Politics.

With lines out the door and around the block, hundreds of people could not get in the packed Rockefeller Chapel to see Sanders return to the same building he graduated from in 1964. The University of Chicago alumnus and Democratic presidential candidate credits his time outside the classroom for shaping what he calls his democratic socialist views.

"I think about the many many hours that I spent in the basement of Harper Library reading everything, except the books that I was supposed to read for class the next day," Sanders recalled.

After his days in Hyde Park, the Independent senator from Vermont spent the next 50 years fighting for social justice issues, many which he spoke about Monday, including civil, gay and women's rights, climate change, a broken justice system and income inequality.

"American democracy is not supposed to be about billionaires buying elections," he said.

With growing crowds on the campaign trail, Sanders' message has been resonating, especially with young people and lifelong Democrats.

"Even if he doesn't necessarily win, he's definitely speaking out on things that need to be talked about, bringing up good points," said student Darius Pool.

"I do see him as a serious presidential candidate," said another student.

Sanders poll numbers have been gaining, edging closer to Hilary Clinton's lead, but the Institute of Politics' David Axelrod says, don't count Hilary out.

"There is no doubt, she is going to have to fight for the nomination," Axelrod said. "The sooner she embraces that concept and doesn't behave like a front runner, the better off she'll be."

And so far, Sanders is giving Clinton a reason to fight.