You'll need to click on the graphic to see the rather small details here but this is the part I find most interesting, although it sounds macabre: The death rates per capita of major events in world history.
An Lushan Rebellion 5.6% of world population
Genghis Kahn 9.5% of world population
Black Death 9.7% of world population
Worlds Wars + Spanish Flu 7% of world population
I have to let that last one sink in for a moment. Both world wars plus the Spanish Flu epidemic (which killed a distant relative of mine) were less deadly than the Black Death and Genghis Kkan (as a percent of the population).