I recently found this book, "I Never Saw Another Butterfly: Children's Drawings and Poems from Terezin Concentration Camp, 1942-1944," at our public library. It broke my heart. It is so difficult to wrap my mind around the cruelty that exists in this world. Who would hurt a child? But look at the beautiful art work the children made while they were in this difficult place. It is as if by the sheer force of their creative spirit, they were able to move forward each day.
I think that this book would make a solid introduction for an older child to learn about the Holocaust of World War II. Like "The Diary of Anne Frank," this book is from the child's perspective and hence allows a contemporary child to understand history through their empathy for children in the past.