2,500,000 bc, 10,000 bc, 8,000 bc, 3,500 bc, 3,200 bc.
World War I was really the fist "total war" in the sense that practically all available manpower and resources were used to fight the enemy. This meant that there were no "breaks" and very few rules to the fighting.
The Aztecs were pagans according to Conquistadors who were Christians. On behalf of Christianity, the conquistadors committed many monstrosities and those who would not obey them suffered greatly.
