This is a 20-part retrospective image gallery published by The Atlantic online in the latter half of 2011. I meant to post it when it finished coming out, but forgot to until I found it in the bookmarks now. But then, it's not like it ever goes out of date.
It's a lot of material, but I'd strongly recommend looking and reading through all 20 galleries. It's a great history lesson, and far from dull too with the great selection of photos.
The Holocaust part is the most graphic, but somehow it wasn't the most disturbing to me. Perhaps, being Polish and all, with my family quite directly affected by WW2, I got used to it, if you can even use this word in this context.
On the other hand, the Internment of Japanese Americans had the highest shock factor for me. The story and photos were like random bits and pieces of the terrible stuff that happened in Europe/Poland - mass deportations to concentration/extermination camps, creation and liquidation of Jewish ghettos, etc. - but all in a cheerful, safe, family-friendly re-enactment by a high-school theatre group.
I'm not trying to trivialize it, quite the opposite. It's just the contrast between the imagery that I'm used to and the neatness of how it looked when executed in the US that is really striking to me, with the goals and prejudices in the minds behind both operations being more or less the same. Also the fact that until I saw this gallery I was completely unaware of this dark part of the US history probably contributed to my response to it.
But enough about my own impressions. For good measure, here's a blurb about the gallery from The Atlantic:
World War II is the story of the 20th Century. The war officially lasted from 1939 until 1945, but the causes of the conflict and its horrible aftermath echoed for decades in both directions. While feats of bravery and technological breakthroughs still inspire awe today, the majority of the war was dominated by unimaginable misery and destruction. In the late 1930s, the global population stood at approximately 2 billion. In less than a decade, the war between the nations of the Axis Powers and the Allies resulted in some 80 million deaths -- killing off about 4 percent of the whole world.
This series of entries was published weekly on TheAtlantic.com from June 19 through October 30, 2011, running every Sunday morning for 20 weeks. In this collection of 900 photos spread over 20 essays, I tried to explore the events of the war, the lives of the people fighting at the front and working back home, and the effects of the trauma on everyday activity. These images still give us glimpses into the experiences of our parents, grandparents and great grandparents, moments that shaped the world as it is today.