Rifles on display in a shop at Aurora, Colorado. (Getty)

A gunman killed at least 12 people and injured 59 more when he opened fire on a midnight screening of the new Batman film in Aurora, Colorado last week. The shooting — much like the 1999 attack on a school in nearby Columbine — has revived the debate over just why such massacres happen in the US and whether more needs to be done to crack down on gun ownership. Below are some pieces that examine these issues: Read more