Most survivors of World War II's Nazi concentration camps are now in their 80s and 90s, and soon there will be no one left who experienced the horrors of the Holocaust firsthand -- no one to answer questions or bear witness to future generations. But as we first reported two years ago, a new and dramatic effort is underway to change that by harnessing the technologies of the present and the future. To keep alive the ability to talk to -- and get answers from -- the past. Our interview with Holocaust survivor Aaron Elster, who spent two years of his childhood hidden in a neighbor's attic, was unlike any interview we have ever done. "Aaron, tell us what your parents did before the war," Stahl asked Elster. "They owned and operated a butcher shop," Elster said. It wasn't the content of the interview that was so unusual. "Where did you live?" Stahl asked. "I was born in a small town in Poland called Sokolów Podlaski," Elster said. It's the fact that this interview was with a man who was no longer alive. Aaron Elster died four years ago.

We may not have robot maids just yet, but you can still outsource a surprising number of household chores to machines. There are specialized robot cleaners that can do just about everything, short of putting your dishes in the dishwasher and making your bed. Robot vacuums have been on the market for more than a decade, and they've gotten pretty savvy. Autonomous vacuums can work on carpet or hard floors and can be set to run on a preset schedule, so by the time you return home, your floors are clean and your vacuum is back at its charging station. Sensors and bumpers help the vacuum map the room, avoid obstacles and figure out the dirtiest spots to focus on.

Pinchas Gutter goes out of his way to find me biscuits. In a sun-baked living room in his north London home, he opens a packet of Rich Tea, sits down and tells me about the Holocaust. Gutter was seven years old when the second world war broke out. He lived in the Warsaw ghetto for three and a half years, took part in its uprising, survived six Nazi concentration camps – including the Majdanek extermination camp – and lived through a death march across Germany to Theresienstadt in occupied Czechoslovakia. "Remembrance is the secret of redemption, while forgetting leads to exile," he says, quoting Baal Shem Tov, the founder of Hasidic Judaism.