As the war began, experts thought that technical advances in weaponry would bring about a quick victory, but the reality was different as armies resorted to trench warfare on the Western Front.
With deadlock in the trenches, the great powers searched for other ways to break through.
The battles of Verdun, the Somme and Passchendaele were three of the worst of the war, yet soldiers sought to keep their sanity with music, sport and theatre.
By the start of 1917, the strain of war was so great that half the French army mutinied, while in Russia the whole regime was overthrown.
This part looks at the poverty and unrest among the German people, how the Americans finally joined in and how the war ended.
Documentary series telling the history of the Great War concludes with the post-war peace negotiations and the unfair treatment of the defeated Germans and Austrians that gave rise to their anger, poverty and unrest.
