there wouldn't be a holy war.

Well, technology would be far more advanced thats for sure!

Beyond that I have no idea, maybe slightly less violent, but thats about it as far as I can see. Too many variables to honestly say for certain what would happen.

Thousand years more advanced at science at least and I think there would be killing but not wars.Without religions, people actually couldn't blame anyone else than themselves about their life.

There would be a lot more racial wars of genocide.

humans will always find a reason to fight, yes the world would be diffrent without religion, it could be worse as it spread good ideas, i think that now religion is useless but back then at the time of the roman empire it was very helpful.

i can see that. then again maybe the Holocaust would not have happened. (persecution and mass murder/genocide is a sin)

Um, sorry but tough nuts. I'm an agnostic atheist and it doesn't depress me that you've made different life decisions than me. Just don't sweat it! You shouldn't get hung up on what other people believe. In fact, keeping an open mind is highly enlightening.

On the original topic, this question is more complex than it first appears to be. How do we define religion, firstly? Religion can be anything. People say that Buddhism isn't a religion but a way of life, but I don't accept that judgement. What sets the practices or the belief system/philosophy of Buddhism from that of any of the Abrahamic religions or anything else?

Agnosticism is also a religion, more or less. People sometimes think that agnostics simply do not "believe" in religion but I don't think that definition is quite accurate either. Agnosticism is essentially the realization that whatever it is you believe in, it cannot be proven or disproven. Thus the term, "agnostic atheist."

By asking the question in the first place you are trying to get us to tell you that the world would be better without the Crusades or Jihadist groups but those are extreme ends of the spectrum. There are equally extreme positive products of religion. Philanthropy being one. In the end, if there were no organized bases of shared belief systems that groups of people shared and contemplated in an established setting, we would be sitting in practically the same spot.

Then again, there is this:

I don't think there would be less war, they always make up a reason. And as much as religion has divided people it has united them. Religion stops people from doing this like killing or stealing because of the fear that there's a God watching you. Religion works like a conscience, gives people principles.

Yet that didn't stop the inquisition and the crusades, where hundreds of thousands of people were killed in the name of god and religion, right? 

I don't think that all religion is wrong and that a world without no religion would be a much better world. There are some religions who uphold sentiments of peace and human progression through science and self improvement, and then there's some religions who uphold completely contrary sentiments, which unfortunately set us back almost a thousand years in terms of scientific evolution and human morals.

Me, i'm a Wiccan in religion, and a geneticist in science. Those two beliefs co-exists with each other, because they don't go head to head in nonsensical backwards dogmas. 

Well, organizations like the church have always been corrupted but it's not the religion's itself fault. Christianity for example seems to be too open, some people see it as just a belief for a God and then for others it's just a way of life, where you love others like you would love yourself just for being people like you and all the rest comes from that love you feel. What I'm trying to say is that for some people by doing killing for your religion you can be either a true Christian or not a real Christian at all since there doesn't seem to be a clear definition, everyone has it's interpretations. But yes, nowadays religion at least SHOULD teach sentiments of peace, love and generosity.

Me, I'm like a mix between Christian and atheist. I wouldn't like being an extremist on either side, just let them co-exist. But I've had doubts lately since I'm from a country where basically everyone is Christian and people don't expose themselves to other types of religions and the internet is almost purely atheist. =/ But it's kind of sad to think theres an infinite universe with no reason of being at all, neither does a life in which we waste so much time in and that all the people that have died throughout history just have died and that's it, isn't it? It's just kind of the happier options.

I thought it twice before clicking done because I was kind of rambling talking with myself lol. =)