Holocaust Thinking Question

World controlled by humans, influenced by humans. Their thoughts, theirs acts, will change the world. A big society should be a big peace group, there shouldn’t have any hates or wars. But some people or some races don’t think so. They think no one as good as them, they are the best ones. So people followed by their leaders, as the world follows by the humans. They are turning jealousy, so the society changed.