Heidi Yewman became an advocate for stricter gun control after the Columbine Shootings in 1999. Yewman graduated from Columbine, and her high school teacher was killed in the attack.

Now, Yewman leads trainings on how parents can ask other parents whether or not they have guns in their households before their children visit other homes. She collected stories of gun violence in her book, "Beyond the Bullet, Personal: Personal Stories of Gun Violence Aftermath."