The top three largest examples are thought to be the Crusades of the Middle Ages, the Spanish Inquisition, and the burning of witches. These three events, totaling over 264,000 killed, are thought to be the largest atrocities perpetrated by one or another form of Christendom.
According to University of Hawaii political scientist Rudolph J. Rummel,1 the total number killed in all of human history is estimated to be about 284,638,000. Of that number, 151,491,000 were killed during the past 100 years. The single largest killer in all of human history is, by far, atheistic Communism with a total of 110,000,000 … over 1/3 of all people ever killed! If we add to that number just two other regimes where religion of any sort was strongly discouraged, Nazi Germany and Nationalist China, the number rises to 141,160,000.
Almost 50% of all the killings in human history were committed in the past 100 years by
regimes that either actively promoted atheism or strongly discouraged religion. We have
not considered the over one billion abortions, where Christianity seems to be particularly unwelcome. When the murders of history are tallied up, it is very clear that atheism (rebellion against God or hate of God or not believing in God) is the most dangerous philosophy ever embraced by humanity. The most effective restraint on
mankind’s inherently evil tendencies is faith in God through Jesus Christ, a faith that
actually follows the teachings and commands of Jesus Christ as a daily way of life.
Here the link to facts/ statistics
Peschken's Blog 
Comments on: "Christianity has NOT killed more than atheist or war combined." (4)
Some little details: a) Most nazis were christians. b) it wasn’t for the lack of trying that the religions were so bad at killing – they just lacked modern tech. c) The communistic regime didn’t kill because it was atheistic, as much as Hitler didn’t kill because he was pretty small. The communists were also atheists, but their atheism was not the driving force.
Most Nazis were Christians ? Nazis hated Christ, Christians, Jews, Catholics. All Communist, Socialist, Atheistic, Totalitarian regimes killed in the name of their own secular Anti God ideology, that they try to impose on all people. Research history and accept historic facts.
It’s not nice to lie, you know that. So please don’t. After I told you reality, you can’t claim ignorance anymore, so stating these things IS a lie, plain and simple. Read the statistics, the overwhelming majority of nazis were christians. The churches even SUPPORTED the nazis (even after the war by helping nazi war criminals escape justice).
And some regimes were also atheistc, true, but that doesn’t imply that they killed, because they were atheistic, that’s as dumb as trying to claim that Hitler was a mass murderer because he had shoe size 13.5 – in reality, he was a mass murderer that had shoe size 13.5.
And, as I already told you, it was not the lack of trying that prevented the religions from killing more people – it was the lack of people and the lack of technology to do so.
LOL..Accept reality instead of your own phantasy world.