From Edge:

Pinker201 In sixteenth-century Paris, a popular form of entertainment was cat-burning, in which a cat was hoisted in a sling on a stage and slowly lowered into a fire. According to historian Norman Davies, “[T]he spectators, including kings and queens, shrieked with laughter as the animals, howling with pain, were singed, roasted, and finally carbonized.” Today, such sadism would be unthinkable in most of the world. This change in sensibilities is just one example of perhaps the most important and most underappreciated trend in the human saga: Violence has been in decline over long stretches of history, and today we are probably living in the most peaceful moment of our species’ time on earth.

In the decade of Darfur and Iraq, and shortly after the century of Stalin, Hitler, and Mao, the claim that violence has been diminishing may seem somewhere between hallucinatory and obscene. Yet recent studies that seek to quantify the historical ebb and flow of violence point to exactly that conclusion.

More here.