CHICAGO (CBS) — Thousands of students walked out of classes across the Chicago area on Friday, to send a message against gun violence.

The demonstration was part of the the second nationwide school walkout to protest gun violence in the wake of the deadly school shooting in Parkland, Florida. Friday’s marches were timed for the 19th anniversary of the infamous Columbine High School massacre in Colorado.

At a Chicago elementary school, the day had special meaning for one student. Grace Bauer’s father, Chicago Police Cmdr. Paul Bauer, was shot and killed while trying to apprehend a suspect in February.

“When will this end? This cannot be solved by thoughts and prayers. This can only be solved by action,” Grace said Friday outside her school.

Students taking part in the walkout in Chicago were meeting at Grant Park for a rally to include speeches and poetry readings.

Friday’s national school walkout mostly focused on high school students, but some universities and elementary schools also joined the demonstration.

Students at South Loop Elementary school began walking out at 1 a.m. The school recently was affected by gun violence, because Grace Bauer, the daughter of slain Police Cmdr. Paul Bauer, is a student there.

So hundreds of South Loop students marched to protest gun violence while honoring the late police commander.

After 13 seconds of silence to mark the 13 lives lost at Columbine High School in 1999, students spoke about the need for common sense gun laws.

Grace Bauer was the first to speak.

“When I heard about the Parkland shooting, my eyes glazed over the news. Why? Because a day before, my father was shot downtown. The media moves on, tragedy after tragedy, but we will not. We refuse to forget the victims of gun violence close to our hearts,” she said.

Donya Kameli said one of her friends died in the shooting at Marjory Stoneman Douglas High School in Parkland, Florida.

“I’m doing this to honor her, because she was an amazing person, and I wish I saw her one last time before she died. So I’[m honoring in her memory,” she said.

After the speeches, students released balloons in honor of the victims of gun violence, including Cmdr. Bauer, and the 17 victims of the Parkland school shooting.

Many students wore orange, the same color hunters wear to make sure they are visible to other hunters in the woods. It’s also the color adopted by the family of Hadiya Pendleton, an honor student killed by a stray bullet five years ago.

Pendleton, 15, was shot and killed in a Bronzeville neighborhood park while walking home from school, just days after performing with her school band at President Barack Obama’s second inauguration.

Mike Puccinelli