It is 20 years since heavily-armed Chechen rebels took an entire theatre full of people hostage.
They threatened to kill them all if the Russian government didn't call off the war in Chechnya. When Russian special forces stormed the theatre they let off gas to stun the Chechens - it killed many of the hostages as well. In this programme first broadcast in 2012 Dina Newman speaks to one of the survivors, Prof Alex Bobik.
(Photo: Chechen rebel on Russian TV. Credit: Getty Images)