(CBS) —  Thursday would have been Hadiya Pendleton’s 19th birthday. Now the date has become a day to speak out against gun violence.

Pendleton is the Chicago high school student who was fatally shot in January 2013 at a South Side park, an incident that shone a light on the violence that occurs in city neighborhoods.

CBS 2’s Susanna Song reports from Harold Washington Park, where hundreds gathered to promote peace as part of Project Orange Tree. Participants wear orange.

“We want people to realize there is hope. Don’t let gun violence become the norm. It seems like it is, but if you accept it, it’s only going to get worse,” founder Nza-Ari Khepra says.

Hadiya’s father, Nate Pendleton, says he and his family visited her grave on Thursday and, as always, brought Twizzlers, her favorite candy.

“There is no easy day,” the restaurant owner said. His restaurant was also decked out in orange.

Skylines and bridges across country will turn orange at dusk. That includes the Crain’s Communications building in Chicago.