With 27 believed dead, NBC News puts today's horrific Connecticut school shooting in the context of others our country has weathered, and it's as devastating as it seems: It's worse than Columbine. The Sandy Hook Elementary shooting is the second worst in our nation's history, topped only by Virginia Tech and its 32 fatalities in 2007; 13 people died in 1999's Columbine massacre. One parent with a son at the 600-student school described the experience of waiting to see if his child was OK as "the most terrifying moment a parent can imagine." Seeing him "was the greatest relief in my existence." Click to read the latest on the massacre. (More school shooting stories.)