AURORA, Colorado (CNN) -- One year after a gunman killed 12 people in an Aurora movie theater, the city is marking its losses with solemn moments and a continuing debate over the place of guns in society.
Tom Sullivan was part of an observance at a state park Friday, where volunteers read aloud thousands of names of victims of gun violence.
His son, 27-year-old Alex Sullivan, died in the Century 16 theater on July 20, 2012.
"A guy walked into a movie theater with a 100-round drum, and one second my son was watching a movie and the next second he was dead," Sullivan said.
The ceremonial reading, which lasted more than 10 hours, ended at 12:28 a.m. Saturday, the moment when the shooting began one year earlier.
The event was part of the "No More Names" bus tour, sponsored by New York Mayor Michael Bloomberg's group, Mayors Against Illegal Guns.
Carlee Soto came to mark the Aurora killings, although she lost her sister five months later. First-grade teacher Victoria Soto, 27, was killed in the elementary school massacre in Newton, Connecticut.
"Every situation is different," Carlee Soto said. "From a movie theater to an elementary school to a church, it's all different. But we all carry the same grief, and we all share the wanting to change our gun laws."
A handful of gun rights advocates peacefully protested the event Friday. One of them, Rob Blancken, said all Coloradans should remember the tragedy.
"It's also a tragedy that a firearm was not allowed to be used inside that theater that may have prevented that tragedy," Blancken said.
The Colorado gunman sprayed bullets into a packed midnight screening of the Batman film, "The Dark Knight Rises." The rampage a year today left 70 people injured.
The city of Aurora scheduled a series of events Saturday, including "healing activities" such as meditation, music, counseling and yoga. Some activities were scheduled for the newly-opened Aurora Strong Community Resilience Center, which is designed to teach trauma coping skills.
James Holmes, 24, is expected to be tried in 2014 for the Aurora shootings. He has pleaded not guilty by reason of insanity.
Ted Rowlands reported from Aurora, Colorado, and David Simpson reported and wrote from Atlanta.