| In 1908 Austria-Hungary annexed Bosnia and Herzegovina. War was avoided | Approaching War |
| In the 5 years prior to the First World War, arms-spending rose by 50% | |
| In 1904 the "Entente Cordiale" made allies of sworn enemies, Britain and France | |
| The "The Triple Entente" of 1907 brought Russia into this alliance | |
| The assassination of Archduke Franz Ferdinand in June started the war in August | |
| 65 million people fought in the war. Around five million of those were British | The Numbers |
| Soldiers had to be 18 years old officially. The youngest British soldier was 12 | |
| 12 million letters were delivered to soldiers on the front line every week | |
| 628 Victoria Crosses were awarded, a quarter of them to men who had died | |
| A quarter of a million horses and mules died on the Western Front | |
| The first functioning unmanned aerial drone was developed in 1918 | Innovations |
| Wristwatches were not worn by men until World War One | |
| Stainless steel was invented and used in aircraft engines and medical instruments | |
| The world's first blood bank opened in 1917 on the Western Front | |
| Daylight Saving Time began in Germany in 1916 as an effort to save coal | |
| One third of casualties were received inside trenches rather than on open ground | Trenches |
| Bugs, rats, lice and even frogs lived alongside men in the trenches | |
| A day in the trenches often began with "Morning Hate" | |
| For every 20,000 men 300 gallons of rum were given to help keep them warm | |
| Most of the work in trenches was done under the cover of darkness | |
| Germany was the first to use flamethrowers on February 26, 1915 | Weapons |
| Tanks, a British innovation, appeared on the battlefield on 15th September 1916 | |
| The age of air warfare began in World War One | |
| Both sides used chemical weapons against each other | |
| The main weapon was artillery. It caused roughly half of all deaths | |
| The "Dreadnaught" was a new kind of battleship, faster and tougher than others | At Sea |
| They were vulnerable to mass attacks from small torpedo boats | |
| The first destroyers were built to counteract these small boats and their torpedoes | |
| Submarines were first used effectively in WWI. The German U-Boats were feared | |
| Great Britain laid almost 200,000 naval mines to protects its east coast | |
| The Battle of Passchendaele left an estimated 860,000 casualties | Battles |
| The Somme Offensive advanced the Allies 7 miles, costing over a million lives | |
| After huge losses in the Battle of the Marne the first trenches were dug | |
| The Battle of Jutland was the largest naval battle of the First World War | |
| The Battle of Verdun was the longest battle of the First World War. | |
| Pilots who brought down 5 enemy planes were given the title "ace" | In the Air |
| Observation balloons were included in the list of victories for pilots | |
| The "Jagdstaffeln" were specialised German fighter squadrons | |
| During "Bloody April" of 1917 the British lost 245 aircraft out of 365 | |
| "Archies" were anti-aircraft guns which fired shells that fragmented in the air | |
| Men who refused to fight on compassionate grounds were imprisoned | Civilians |
| A German airship attack on London mistakenly dropped its bombs on Hull | |
| To replace the 5 million men who had gone to war, 1.6 million women stepped in | |
| Dorothy Lawrence impersonated a man so that she could serve as a soldier | |
| By April 1916 Britain was said to have only enough wheat left to last 6 weeks | |
| Around 2 million servicemen died from disease or malnutrition rather than injury | Casualties |
| 8.5 million troops are thought to have been killed, 750,000 of them British | |
| 21 million troops were wounded, including 1.5 million British | |
| As well as servicemen, up to 13 million civilians were also killed | |
| Russia suffered the highest number of casualties: over 9 million of them | |
