" The killing of tens of thousands of people within a matter of minutes, leaving hundreds of thousands suffering for years with radiation sickness, their lives made very terrible because of the suffering that they continue to go through for so long, until they mercifully died. "

Change the " tens of thousands " to " tens of millions " and you describe the Black Plague of the Dark Ages, and the Spanish Flu of 1918.

Which war caused those two genocides ?