TOM HORTON

Traces the key moments in the First World War

Arch Duke Franz Ferdinand, the heir to the AustriaHungarian throne, is shot dead in Sarajevo by a political dissident.

Austria-Hungary sends troops to the Serbian border.

Serbia and Russia mobilise their armies. Germany declares war on France. Britain declares war on Germany after they invade Belgium. USA declares neutrality. A Royal Navy cruiser is sunk by German mines in the North Sea, killing 150 men and inflicting the first casualties on Britain. First members of the British Expeditionary Force arrive in France to assist with the land campaign. Lord Kitchener makes his first call for more men to enlist in the military. Defence of the Realm Act (DORA) gives the UK government sweeping powers to suppress public criticism and imprison people without trial in order to aid the war effort. Japan declares war on Germany and British Army troops see their first land action in the Battle of Mons. First battle of Ypres begins as Allied and German troops attempt to reach sea ports in Belgium. Britain and the Ottoman Empire declare war on each other. German battleships bombard Hartlepool, Whitby and Scarborough, killing 137 civilians. The first Zeppelin raid on London kills seven people. Battle of Loos begins and the British forces use gas for the first time, however wind blows it back onto their own troops, killing seven and injuring 2,625. The third day of the Battle of Loos sees the highest British death toll of any battle so far, with 8,246 men being killed. Battle of Verdun, which causes almost a million casualties over 10 months, begins. The Battle of Jutland begins between German and Royal Navy fleets of dreadnoughts. Neither side claims decisive victory and no other naval battles are fought for the rest of the war. German U-boat torpedoes British passenger liner Lusitania, pictured below, drowning almost 1,200 people including many children. Right: A sailor pays his respects to victims.