(CBS News) Seventy years ago today -- October 6, 1943 -- a group of rabbis and Jewish war veterans staged a small march in Washington to draw public attention to the Holocaust then taking place across Nazi-occupied Europe. We are still learning more about just what happened, both from archives and from the personal witness of those who somehow survived. Our Cover Story is reported now by Lee Cowan:
She remembers it vividly: "The train arrives, people getting out, lining up on the platform, and pretty soon they will be told, 'Men to one side and women to the other."
To talk with Irene Weiss is to touch the Holocaust in a truly personal way.
She's a survivor, and yet -- some seven decades later -- she can barely believe it had actually happened.
"At first, this was pretty hard to talk about, wasn't it?" Cowan asked.
"Yes. It was extremely difficult. And then I realized that we have to share the story. We can't let people forget it."
She was just 13 when the boxcar carrying her and her family arrived at Auschwitz on that all-too-busy platform.
Weiss knew little of what would come of her when the doors of the cattle car opened: "They were barking orders to get out. My father and 16-year-old brother lined up with the other men and boys, and the women and children and elderly in another line."
"Where did your mom go?" Cowan asked.
"Well, she and a very large number of the people from the train were headed right to the gas chambers," Weiss said. "Within a half hour, they were all dead."
That was her childhood reality. But the older she grew, the more unimaginable it all seemed -- until one day, she heard about a set of photos that she never knew existed. They were taken by the Nazis on the Auschwitz platform on the very day Irene arrived.
A picture captured that very moment: Irene to the left, alone on the Auschwitz platform: "I'm leaning in to see where my little sister went."
"The very first thing we asked is, 'When are we going to see our families?' " she said. "And they pointed to the chimney and they said, 'That's where your parents are. That's where your family is.'"
"They pointed to the chimney?"
"The chimney. And we ignored it. We ignored it totally. It cannot be."
And then there's this photo that captured Irene's family waiting in line for the Auschwitz gas chamber.
"These two little boys are my two little brothers, and for a long time I could not find my mother here, and I was very unhappy," Weiss said. "And then one day this little face here, sticking out, and I looked with a magnifying glass, and I found her. Ah, yeah, that's the one."
The Holocaust, it seems, continues even now to reveal its horrific reality -- and not just to survivors like Irene Weiss.
At the United States Holocaust Memorial Museum in Washington D.C., a 13-year project has uncovered evidence that the number of places where the Holocaust was put into practice was actually far more numerous than anyone imagined.
Geoffrey Megargee, the lead editor of a multi-volume encyclopedia being written on the Holocaust, said that when he started his research, his sense of the scope of the number of sites implementing Hitler's orders was in the range of 5,000 to 7,000, which to him was "an astounding number."
He now says the total to 42,500 -- six times what he originally thought.
"Exactly," he said. "When you put them all together, this was a shock."
Megargee's research doesn't change the number of people exterminated; What it does is enumerate the mind-boggling number of concentration camps, killing centers, ghettos, brothels and forced labor camps where the Nazis persecuted not only Jews, but Poles, homosexuals, Soviet prisoners of war, and many others, too.