Which is the worst country in the whole of human history?

i mean which country has committed the most crimes, killed the most people, etc.Great britain, USA, france, germany, spanish, mexican, italians, egypt, japan, china, mongolia, iraq. They are just a few countries to think about. im not just looking for countries which have committed crimes recently, you could go back through history to the romans or egyptians. You could probably make an argument for every country