What would the world be like without religion?

If there were no religion, then the universe will be anything like it is today. But who could say what that would be like? How would a world be born, without religion? How could the cave man, without religion, have explained the meaning of life? How would Greece or India's cultures have prospered without religion? When a tsunami destroyed their homes, what story would the leader of a group of people have told his people? Only in the last few years have we grasped the mechanics behind tsunamis... Before that, there is a whole lot of history and I don't see how people could have gone through those times without building a religion to see them through.