Religion has brought untold hardship ip to the world. If there was no religion,i believe the world would have been in peace. One of the key issues is supremacy of belief and faith. This religion or belief, sometimes is forced on the people and when the reject it they are called all manner of names and sometimes it leads to the death of the person for refusing to be a member.
Most civilization in history have their respective beliefs and while the others have been conquering and extending their territories, it's also one of the reasons why they were attacking other communities to push their religion and belief to them. But I think that it has changed these days, you'd see the purity of some of them who are really living in it with harmony and peace.
In my country, there was a systematic killings that took place and it was called christian genocide.
This is sad, from which country you are?