Poland marks the 70 year mark since the beginning of World War II. As a historian, I’ve always believed this was the defining event of human history. The best of people and the most evil part of our nature was on display for six long years. So many things about our world changed forever, and to think my grandparents were there. I’ll be thinking about the sacrifices they made today, and hoping the better angels of our nature make better decisions in the future.