"What's 'the Holocaust'?" my 11-year-old son asks me. I take a deep breath as I gauge how much to tell him. He's old enough to understand that prejudice can lead to hatred, but I can't help but feel he's too young to hear about the full spectrum of human horror that hatred can lead to.

I wrestle with that thought, considering the conversation I recently had with Ben Lesser, a 91-year-old Holocaust survivor who was just a little younger than my son when he witnessed his first Nazi atrocity.

It was September of 1939 and the Blitzkrieg occupation of Poland had just begun. Ben, his parents, and his siblings were awakened in their Krakow apartment by Nazi soldiers who pistol-whipped them out of bed and ransacked their home. As the men with the shiny black boots filled burlap sacks with the Jewish family's valuables, a scream came from the apartment across the hall. Ben and his sister ran toward the cry.

They found a Nazi swinging their neighbors' baby upside down by its legs, demanding that the baby's mother make it stop crying. As the parents screamed, "My baby! My baby!" the Nazi smirked—then swung the baby's head full force into the door frame, killing it instantly.

This story and others like it feel too terrible to tell my young son, too out of context from his life of relative safety and security. And yet Ben Lesser lived it at my son's age. And it was too terrible—for anyone, much less a 10-year-old. And it was also completely out of context from the life of relative safety and security Ben and his family had known before the Nazi tanks rolled in.