Our oldest has had some course work on WWII but not alot/enough. By the time I was in fourth grade I was consuming books especially about WWII. My kids have not taken to books as I did but they seem to be catching the bug though our youngest has some real reading difficulties that we and the school cannot figure out.
The one great asset they have, that I did not, was TV.

The History, military, science, etc channels are great. Yesterday I was watching a documentary about a photo album that was from the assistant commander at one of the Auschwitz death camps.
The documentary was also showing the contents of the Jacob's photo album. If you have seen photos of the death camps showing people being processed at the trains those are from this photo album. The album was found by a camp survivor after she was liberated. She was in SS guard barracks that had been turned into a hospital and in the night she got cold so she opened a drawer looking for a blanket. Instead she found the album.
She had been sent to camps from Hungry. Everyone in her family and most of the people she knew died in the camps. 80% of the arrivals were gassed the day they arrived. When she opened the album it was photos of people she knew. Including some of her family as they were processed. Shortly after the photos were taken they were all dead.
What are the odds she would find the photo album?
By the time I was my oldest kids age I had already seen far worse photos of dead soldiers and civilians in WWII. And I had seen the stack of dead bodies in the death camps. I think because I had seen these photos at a young age I am somewhat inoculated to the horror they represent.
Most of the photos in the documentary were not graphic which is what makes them so much worse. The officer's album was just like any other photo album. People happy. Having fun. Smiling, Singing and having a great time. What was scary is the normality of these people. The realization they were killing 1,000 people a day but then they could sit down to dinner with white clothes and wine.
One thing I did not know was that Dr. Mengele, who was in some of the photos and these are the only known photos of him at the camp, had not only an MD but a PhD. He was a man who was at some level very intelligent. But yet he and the rest of them were normal looking people who were just Evil.
My inoculation has worn off though in some respect now that I am older. When I see the babies, the toddlers, the older children in the photos and films it still shocks me. The idea that these people could compartmentalize their mind to send children to be gassed is still numbing. I know they did not view these people as people but as worse the people. Thus you can only use the word Evil to describe them. Some of the images in the films I have seen still haunt me.
While I was watching the documentary both kids came into the room. I wanted to change the channel because the youngest is too young to understand. And I did not want the oldest to have to deal with the photos. But they NEED to know what happened. They need to know that what the Germans did is NOT unique. The Germans were, as one of the researchers said, "professional", in what they did. They were very efficient.
Other people in other times have done the same as the NAZIS. And in some cases killed even more people even the 20th century. What is scary is that the mindset that allowed the SS guards to do what they did is not unique to any nationality or time.
And that lesson ALL children should know. No matter how painful it is to deal with the reality. I left the channel as is and answered some questions....
Later,
Dan