First,  I would say that ancient Greece is the cradle of western civilization and the Spanish Inquisition was also  very much a part of that western civilization. It was that kind of violence they brought to America which began the genocide of native people there. 
Genghis Khan was the founder of the Mongol Empire or civilization if you will. Same thing with the Aztecs and the Incas. Also very violent and destructive cultures. In other words, where you have civilization, you have systematic oppresion, organized violence and destruction of the natural habitat. 

What we have now is the same his but instead of horses and spears we have tanks,  automatic weapons and atomic bombs. Ok, so let’s talk about today, where should I start? The Iraq war? The insane destruction of the rain forests all over the world? The shootings? People are dying like flies man while you sit and on your couch watching TV. 
However violent the ancient Greece, Spanish Inquisition and the Mongol Empire was it is NOTHING compared with what is going on now. And this is not based in ideology, it’s reality. But if you can’t see that you are so deeply in denial and suspect you will never wake up. And that is really sad, because we are now facing the sixth mass death on this planet. And the first ever brought on by a living organism.