CHICAGO — Fifty years ago, the world watched as anti-war protesters faced off against Chicago police during the Democratic National Convention.

On Saturday, some of those present returned to Grant Park to share their memories at a peaceful demonstration against war and police violence.

“I heard about it [and] I went out and started taking pictures and I got fascinated because there was so much stuff going on,” Al Lieberman said. “It was like a circus, a three-ring circus.”

Lieberman was a 29-year-old teacher living in Lincoln Park during the ’68 riots. He had just gotten a new camera and went out to test it at the anti-war protests surrounding the Democratic National Convention in downtown Chicago.

“It caught me,” he said. “I just started taking pictures, and I stayed every day.”

Lieberman took more than 3,000 photos over the course of a week. Protesters raising peace signs as workers raised the John Hancock building. He caught images of peace and protest, upheaval and unrest.

“I saw peace, I saw blood, I saw music in the park, I saw dancing in the park,” Lieberman said. “It was all going on at the same time.”

Lieberman was one of about 125 people who gathered Saturday to remember the riots. Also present was 66-year-old Bob Rudner, who was just 16 when the riots broke out. He said he was watching “2001: A Space Odyssey” when protests spilled over into the movie theater’s lobby.

“The first billy club hits the McCarthy button,” Rudner recalled. “The second hits the back of my head.”

Organizers said the point of Saturday’s march was not nostalgia — but to show the urgency of speaking up when those in power are acting in an immoral way.

“The scars of the riots are still here,” Rudner said. “And we’ve got to confront racism in this country.”