Overview: The question of how the First World War was started has been one of the great controversies of the 20th century. The flashpoint was the assassination in Sarajevo of Franz Ferdinand, heir to the Hapsburg throne. But it was the reaction to his death of a handful of imperial warlords that led to four years of fighting and the death of over eight million people. The producers of this documentary, marking the 80th anniversary of Franz Ferdinand's death, have been round Europe - from Sarajevo to St Petersburg - culling archive film from eight countries to piece together the mysteries and intrigues that led to the Great War.