This Sunday, December 14, marks the 2nd anniversary of the Sandy Hook shootings. After watching the video above, please also click through to watch Sandy Hook Promise's short documentary, "What They Left Behind". It's 30 minutes long, but it's an important 30 minutes to watch. Also please check out Everytown's map of school shootings that have occurred since Sandy Hook. The number should be 0, but it's not. And then make a promise to do something.