Twins who survived Holocaust describe their parents' courage in Bergen-Belsen: "They were just determined to keep us alive"

The Hess family, like millions of Jews, was taken from their home in Amsterdam by the Nazis in 1943. 

After spending time at Westerbork, a transport camp in Holland, the family of four was sent by train in 1944 to Bergen-Belsen, a concentration camp where more than 50,000 people died — including Anne Frank — twins Steven and Marion Hess, just 6 at the time, credit their parents for keeping them together.

"The Holocaust seems like ancient history, so we have to find a way for it not to be that, for it to be a lasting lesson," Marion Ein Lewin told CBS News.