Punisher - what would you say is the most important thing (pick 1-3) for a person in their 20's to know about WWII?

Sterling - FT just had an article (comment section not that serious) about how people don't really need to have a broad knowledge of facts because everything is a click away. If I need to know when the modern state Israel was formed I can just go to the net. If I want to know when Mexico lost control of California, I just go to the net. I'm interested in history but the need for me to know the exact details becomes less and less important. Also the reason for knowing things is less and less important. Slavery in the USA was mentioned above, but I'd argue that the civil rights movement is probably more important to someone in 2010 because there are still people who were alive and discriminated against (my father and his family for instance) during that time.