During the Second World War, analysts pored over stereoscopic aerial reconnaissance photographs, becoming experts at identifying potential targets from camouflaged or visually noisy backgrounds, and then at distinguishing between V-weapons and innocuous electricity pylons.

Research shows that homicide rates in many countries are falling; leading experts from around the world believe that global rates of homicide and other interpersonal violence - such as child abuse and domestic violence - could be reduced by as much as 50% in just 30 years if governments implement the right policies.