This Saturday, students and adults alike will take to the streets, calling for an end to gun violence at schools. The official March For Our Lives in Washington, D.C., was started by teenage survivors of the deadly high school shooting in Parkland, Fla. But it has since grown to include more than 800 sister marches across the world, including the one in Denver. If you plan to attend the Denver march, here’s what you need to know: What is it: Shannon Hayes, a member of the event’s organizer Never Again Colorado, said the march is calling for an end to gun violence.