Atop the piano in Ruth Katz’s childhood home was a picture of a man she knew only as “Uncle Oskar.”

In this clip, Walter Rosenblum, an army photographer during World War II, talks about the photos he took on D-Day, June 6, 1944.

Among the photos Walter Rosenblum took on the morning of D-Day was an iconic shot of an exhausted young lieutenant on a rocky beach, gazing past the camera while he and several others perform first aid on a group of men they’d tried to rescue from a wrecked boat.