@coldjoint,
When they took Baghdad (1258), the Mongol killed hundreds of thousands people, mostly Muslims, in the space of a few days, then proceeded to burn what was then the largest city on earth, and to destroy all the manuscripts they could find in its many libraries.
In the second century AD, Hadrien's armies slaughtered one to two million Jews in Judea in the span of a few months, to teach them not to revolt against Rome.
In the space of a month or so, in 1994, Hutu extremists mowed down an estimated one million Tutsis with machettes.
During WW2, the Nazis killed about 11 million people in their camps, half of the Jewish.
Should I go on?