Anti-Semitism.

Jews could be found in all walks of life, farmers, tailors, seamstresses, factory hands, accountants, doctors, teachers, and small-business owners. Many children ended their schooling early to work in a craft or trade; others looked forward to continuing their education at the university level. Whatever their differences, they all had one thing in common, by the 1930s, with the rise of the Nazis to power in Germany, they all became potential victims, and their lives …

…the destiny of others. Anti-Semitism began as just a few negative views and misunderstanding amongst different cultures. But these negative views evolved into negative thought which evolved into negative actions, which evolved into a negative world. Ideas and opinions came make an impression so powerful that it can change the whole world. "Ideas are more dangerous than guns. We wouldn't let our enemies have guns, why should we let them have ideas?" -- Josef Stalin.