I finally had a chance to sample the VR and MR experiences offered by  New York's prescient Tribeca Film Festival, which added the immersive Arcade last year, and has guided it skillfully into the one of the world's greatest showcases of VR art, installations and storytelling. Like their film festival, some featured experiences will have a long and prosperous life, some may end up in museums, and some will be once-in-lifetime experiences, site specific experiments without a business model.

Pinchas Gutter sits comfortably in a chair, his hands resting in his lap, and answers questions about his Holocaust experience with ease. His young interlocutors nod, cradle their chins and think of more queries. But this is no ordinary Q&A session between a survivor and young people. Gutter is not actually there, though the 85-year-old may as well be.

You've read about the Holocaust in books and seen it portrayed in films. But it's another experience entirely to walk through the site of a concentration camp in virtual reality, led by a survivor who lost his entire family there. The Last Goodbye, which debuts at the Tribeca Film Festival this week, follows Pinchas Gutter as he makes his final pilgrimage to Majdanek, a former Nazi Germany extermination camp in occupied Poland. It's a trip he's made many times, but this one has a specific purpose: to capture his account of the Holocaust so we never forget that it actually happened.