Twenty five years ago, at the height of the cold war, 19-year-old Mathias Rust flew a daring 'peace mission' from Helsinki to Moscow. He evaded Soviet Union air defences for 500 miles before landing his single-engine Cessna in Moscow's Red Square on 28 May 1987. He was greeted by bemused and friendly onlookers, but was arrested by the KGB and later served 14 months in prison. In this film he explains in his own words why he did it