Want to know???? Read these:
http://www.bukisa.com/articles/29176_12-infamous-massacres-in-history
And this:
http://en.wikipedia.org/wiki/List_of_wars_and_anthropogenic_disasters_by_death_toll
http://www.bukisa.com/articles/29176_12-infamous-massacres-in-history
And this:
http://en.wikipedia.org/wiki/List_of_wars_and_anthropogenic_disasters_by_death_toll