Like his predecessor, Tsar Ivan, Stalin held on to power with a reign of terror, his purges and his policies destroying thousands of his citizens. Like other tyrants, though, he projected an image of the "great teacher" and when he died in March 1953, the nation went into genuine shock and mourning. Searching the BBC and the former Communist archives, Jim Riordan finds those who experienced Stalin's rule at first hand and examines how Stalin kept his powerful hold on the USSR over a period of 25 years.