Down in the basement of my father's medical office, the trunk sat in the far corner, the Nazi helmet still standing watch on top.

I walked over and circled it, the air around it heavy, as if I was underwater, drifting close to an artifact that held some ancient secret. I held my breath, gripped the surprisingly cold helmet, and set it on the floor, then unlatched the trunk’s brackets and raised the lid. On top lay the army jacket my father wore in the portrait hanging in the family den, its dark green wool softer than I had imagined. Alan held it up, and I saw mysterious emblems: a Roman numeral VII within the shape of a seven-point star, an odd pyramid-shaped gold form surrounded by blue. Four gold bars bordered the cuff of one sleeve. No moth holes, no mildew. The trunk had preserved the jacket well.

Inside the trunk sat a Florsheim shoebox big enough to hold boots. When I took off the lid, photographs spilled out. There were hundreds inside. One showed endless ocean, faint ripples the only clue that the empty expanse was water, illuminated by a cloud-shrouded moon. My father’s seismographic handwriting noted on the back: The English Channel, June 2, 1944. Prelude to the Invasion.

Other photos were of GIs lying on the ground—white bandages on their crowns, arms, and thighs. Of soldiers wearing Red Cross armbands, notations like The Clearing Station on “Utah” Beach, Normandy, June 8, ’44. Of huge circus-sized tents, emblazoned with enormous Red Crosses. Lines of GIs holding plates and cups. Mountains of rubble next to the remains of churches and homes. Expanses of snow, of tanks and bodies covered in snow. Fields covered with white crosses and an occasional Star of David. The boys who died in the Ardennes. A lad in our battalion.

I flipped through the photos, repetitive records of war’s destruction until, at the bottom of the box, different types of images seized my eyes. Rows and rows of blurred stripes that cascaded into a wave. A foot emerged from the chaos, a leg. Many legs. Grotesquely frozen faces. My fingers pinched the top corner and turned the photo over. Nordhausen, Germany.

Nordhausen. What was Nordhausen? Another photo, more focused: a long canal-shaped ditch filled with bodies. An endless row of bodies. The burial of the concentration camps victims. April 15, 1945.

When I tell my friends about this moment, they want to know: What did you feel when you discovered that your father had witnessed a Nazi concentration camp? For the longest time I searched for the word. Fear? Anguish? None felt true, yet how could I not have felt anything at what has come to be one of the defining moments of my adult life?

I tell them the basement went white around me. My lungs pressed against my ribs and I felt desperate to breathe. That I dumped the photos back into the box and ran up the stairs, up and out into the hallway, the smell of rubbing alcohol relaxing my lungs.

Only now have I found the word. Shock. I went into shock.

Moments after I ran up the basement staircase, Alan stood next to me, shutting off the basement light.

“Those photographs were intense,” he said.

I nodded, pain in my temples squeezing my head like a clamp. As we drove back to our family’s home in nearby Metuchen, I placed my purse on my lap and felt the weight of the glass paperweight against my thigh. I closed my eyes and leaned my head against the cold window. Morbid stripes undulated under my eyelids. What, what were those photos doing among my father’s photographs? Why had he made notes on the back of them—as if he had been there—as if he had seen a concentration camp? It wasn’t possible. There was no way he could have seen one of the camps and not have told us.

“Unless you want it, I’ll ship the trunk back to my place along with the other things I’m taking,” Alan said.

“Fine, sure,” I replied. “You can have them.”