Symbolic grave markers are placed April 11, 2013 on the National Mall in Washington, DC as part of a 24 hour vigil held by religious leaders who will call upon Congress to vote on  legislation to prevent gun violence. Photo by Chris Kleponis/ Lifelines to Healing, PICO National Network/Sojourners

Symbolic grave markers are placed April 11, 2013 on the National Mall in Washington, DC as part of a 24 hour vigil held by religious leaders who will call upon Congress to vote on legislation to prevent gun violence. Photo by Chris Kleponis/ Lifelines to Healing, PICO National Network/Sojourners