From NY Times: Last week, the United Nations announced that the world’s popu­la­tion had reached seven billion, but there have been times when it headed in the oppo­site direc­tion, and not in pleasant ways. The savagery of the Mongol conqueror Genghis Khan may have culled the global popu­la­tion by about 11 percent; two bloody upheavals in China — the An Lushan Rebel­lion and the collapse of the Xin Dynasty — each may have felled about 6 percent of humanity. Those are but 3 of the 100 worst atroc­i­ties in history, as cata­loged by Matthew White in “The Great Big Book of Horrible Things,” an amusing (really) account of the murderous ways of despots, slave traders, blun­dering royals, glad­i­a­tors and assorted hordes. Esti­mating the tolls from such horrors is an inexact science, given war’s nature and the mysteries of antiq­uity. The dead­liest “multi­cides” are more plen­tiful in recent centuries, given that there were more people to kill and better ways to kill them on a grand scale. Even so, killings as a percentage of all humanity are prob­ably declining. Here is a look at the sweep of human brutality presented in a time­line. · Go to Popu­la­tion control, marauder style [info­graphic] →